bundle.js

(function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
const io  = require('socket.io-client');
const Peer = require('simple-peer');
},{"simple-peer":59,"socket.io-client":63}],2:[function(require,module,exports){
module.exports = after

function after(count, callback, err_cb) {
    var bail = false
    err_cb = err_cb || noop
    proxy.count = count

    return (count === 0) ? callback() : proxy

    function proxy(err, result) {
        if (proxy.count <= 0) {
            throw new Error('after called too many times')
        }
        --proxy.count

        // after first error, rest are passed to err_cb
        if (err) {
            bail = true
            callback(err)
            // future error callbacks will go to error handler
            callback = err_cb
        } else if (proxy.count === 0 && !bail) {
            callback(null, result)
        }
    }
}

function noop() {}

},{}],3:[function(require,module,exports){
/**
 * An abstraction for slicing an arraybuffer even when
 * ArrayBuffer.prototype.slice is not supported
 *
 * @api public
 */

module.exports = function(arraybuffer, start, end) {
  var bytes = arraybuffer.byteLength;
  start = start || 0;
  end = end || bytes;

  if (arraybuffer.slice) { return arraybuffer.slice(start, end); }

  if (start < 0) { start += bytes; }
  if (end < 0) { end += bytes; }
  if (end > bytes) { end = bytes; }

  if (start >= bytes || start >= end || bytes === 0) {
    return new ArrayBuffer(0);
  }

  var abv = new Uint8Array(arraybuffer);
  var result = new Uint8Array(end - start);
  for (var i = start, ii = 0; i < end; i++, ii++) {
    result[ii] = abv[i];
  }
  return result.buffer;
};

},{}],4:[function(require,module,exports){

/**
 * Expose `Backoff`.
 */

module.exports = Backoff;

/**
 * Initialize backoff timer with `opts`.
 *
 * - `min` initial timeout in milliseconds [100]
 * - `max` max timeout [10000]
 * - `jitter` [0]
 * - `factor` [2]
 *
 * @param {Object} opts
 * @api public
 */

function Backoff(opts) {
  opts = opts || {};
  this.ms = opts.min || 100;
  this.max = opts.max || 10000;
  this.factor = opts.factor || 2;
  this.jitter = opts.jitter > 0 && opts.jitter <= 1 ? opts.jitter : 0;
  this.attempts = 0;
}

/**
 * Return the backoff duration.
 *
 * @return {Number}
 * @api public
 */

Backoff.prototype.duration = function(){
  var ms = this.ms * Math.pow(this.factor, this.attempts++);
  if (this.jitter) {
    var rand =  Math.random();
    var deviation = Math.floor(rand * this.jitter * ms);
    ms = (Math.floor(rand * 10) & 1) == 0  ? ms - deviation : ms + deviation;
  }
  return Math.min(ms, this.max) | 0;
};

/**
 * Reset the number of attempts.
 *
 * @api public
 */

Backoff.prototype.reset = function(){
  this.attempts = 0;
};

/**
 * Set the minimum duration
 *
 * @api public
 */

Backoff.prototype.setMin = function(min){
  this.ms = min;
};

/**
 * Set the maximum duration
 *
 * @api public
 */

Backoff.prototype.setMax = function(max){
  this.max = max;
};

/**
 * Set the jitter
 *
 * @api public
 */

Backoff.prototype.setJitter = function(jitter){
  this.jitter = jitter;
};


},{}],5:[function(require,module,exports){
/*
 * base64-arraybuffer
 * https://github.com/niklasvh/base64-arraybuffer
 *
 * Copyright (c) 2012 Niklas von Hertzen
 * Licensed under the MIT license.
 */
(function(){
  "use strict";

  var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

  // Use a lookup table to find the index.
  var lookup = new Uint8Array(256);
  for (var i = 0; i < chars.length; i++) {
    lookup[chars.charCodeAt(i)] = i;
  }

  exports.encode = function(arraybuffer) {
    var bytes = new Uint8Array(arraybuffer),
    i, len = bytes.length, base64 = "";

    for (i = 0; i < len; i+=3) {
      base64 += chars[bytes[i] >> 2];
      base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
      base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
      base64 += chars[bytes[i + 2] & 63];
    }

    if ((len % 3) === 2) {
      base64 = base64.substring(0, base64.length - 1) + "=";
    } else if (len % 3 === 1) {
      base64 = base64.substring(0, base64.length - 2) + "==";
    }

    return base64;
  };

  exports.decode =  function(base64) {
    var bufferLength = base64.length * 0.75,
    len = base64.length, i, p = 0,
    encoded1, encoded2, encoded3, encoded4;

    if (base64[base64.length - 1] === "=") {
      bufferLength--;
      if (base64[base64.length - 2] === "=") {
        bufferLength--;
      }
    }

    var arraybuffer = new ArrayBuffer(bufferLength),
    bytes = new Uint8Array(arraybuffer);

    for (i = 0; i < len; i+=4) {
      encoded1 = lookup[base64.charCodeAt(i)];
      encoded2 = lookup[base64.charCodeAt(i+1)];
      encoded3 = lookup[base64.charCodeAt(i+2)];
      encoded4 = lookup[base64.charCodeAt(i+3)];

      bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
      bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
      bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
    }

    return arraybuffer;
  };
})();

},{}],6:[function(require,module,exports){
'use strict'

exports.byteLength = byteLength
exports.toByteArray = toByteArray
exports.fromByteArray = fromByteArray

var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array

var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var i = 0, len = code.length; i < len; ++i) {
  lookup[i] = code[i]
  revLookup[code.charCodeAt(i)] = i
}

// Support decoding URL-safe base64 strings, as Node.js does.
// See: https://en.wikipedia.org/wiki/Base64#URL_applications
revLookup['-'.charCodeAt(0)] = 62
revLookup['_'.charCodeAt(0)] = 63

function getLens (b64) {
  var len = b64.length

  if (len % 4 > 0) {
    throw new Error('Invalid string. Length must be a multiple of 4')
  }

  // Trim off extra bytes after placeholder bytes are found
  // See: https://github.com/beatgammit/base64-js/issues/42
  var validLen = b64.indexOf('=')
  if (validLen === -1) validLen = len

  var placeHoldersLen = validLen === len
    ? 0
    : 4 - (validLen % 4)

  return [validLen, placeHoldersLen]
}

// base64 is 4/3 + up to two characters of the original data
function byteLength (b64) {
  var lens = getLens(b64)
  var validLen = lens[0]
  var placeHoldersLen = lens[1]
  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function _byteLength (b64, validLen, placeHoldersLen) {
  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function toByteArray (b64) {
  var tmp
  var lens = getLens(b64)
  var validLen = lens[0]
  var placeHoldersLen = lens[1]

  var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen))

  var curByte = 0

  // if there are placeholders, only get up to the last complete 4 chars
  var len = placeHoldersLen > 0
    ? validLen - 4
    : validLen

  var i
  for (i = 0; i < len; i += 4) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 18) |
      (revLookup[b64.charCodeAt(i + 1)] << 12) |
      (revLookup[b64.charCodeAt(i + 2)] << 6) |
      revLookup[b64.charCodeAt(i + 3)]
    arr[curByte++] = (tmp >> 16) & 0xFF
    arr[curByte++] = (tmp >> 8) & 0xFF
    arr[curByte++] = tmp & 0xFF
  }

  if (placeHoldersLen === 2) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 2) |
      (revLookup[b64.charCodeAt(i + 1)] >> 4)
    arr[curByte++] = tmp & 0xFF
  }

  if (placeHoldersLen === 1) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 10) |
      (revLookup[b64.charCodeAt(i + 1)] << 4) |
      (revLookup[b64.charCodeAt(i + 2)] >> 2)
    arr[curByte++] = (tmp >> 8) & 0xFF
    arr[curByte++] = tmp & 0xFF
  }

  return arr
}

function tripletToBase64 (num) {
  return lookup[num >> 18 & 0x3F] +
    lookup[num >> 12 & 0x3F] +
    lookup[num >> 6 & 0x3F] +
    lookup[num & 0x3F]
}

function encodeChunk (uint8, start, end) {
  var tmp
  var output = []
  for (var i = start; i < end; i += 3) {
    tmp =
      ((uint8[i] << 16) & 0xFF0000) +
      ((uint8[i + 1] << 8) & 0xFF00) +
      (uint8[i + 2] & 0xFF)
    output.push(tripletToBase64(tmp))
  }
  return output.join('')
}

function fromByteArray (uint8) {
  var tmp
  var len = uint8.length
  var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
  var parts = []
  var maxChunkLength = 16383 // must be multiple of 3

  // go through the array every three bytes, we'll deal with trailing stuff later
  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
    parts.push(encodeChunk(
      uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)
    ))
  }

  // pad the end with zeros, but make sure to not forget the extra bytes
  if (extraBytes === 1) {
    tmp = uint8[len - 1]
    parts.push(
      lookup[tmp >> 2] +
      lookup[(tmp << 4) & 0x3F] +
      '=='
    )
  } else if (extraBytes === 2) {
    tmp = (uint8[len - 2] << 8) + uint8[len - 1]
    parts.push(
      lookup[tmp >> 10] +
      lookup[(tmp >> 4) & 0x3F] +
      lookup[(tmp << 2) & 0x3F] +
      '='
    )
  }

  return parts.join('')
}

},{}],7:[function(require,module,exports){
/**
 * Create a blob builder even when vendor prefixes exist
 */

var BlobBuilder = typeof BlobBuilder !== 'undefined' ? BlobBuilder :
  typeof WebKitBlobBuilder !== 'undefined' ? WebKitBlobBuilder :
  typeof MSBlobBuilder !== 'undefined' ? MSBlobBuilder :
  typeof MozBlobBuilder !== 'undefined' ? MozBlobBuilder : 
  false;

/**
 * Check if Blob constructor is supported
 */

var blobSupported = (function() {
  try {
    var a = new Blob(['hi']);
    return a.size === 2;
  } catch(e) {
    return false;
  }
})();

/**
 * Check if Blob constructor supports ArrayBufferViews
 * Fails in Safari 6, so we need to map to ArrayBuffers there.
 */

var blobSupportsArrayBufferView = blobSupported && (function() {
  try {
    var b = new Blob([new Uint8Array([1,2])]);
    return b.size === 2;
  } catch(e) {
    return false;
  }
})();

/**
 * Check if BlobBuilder is supported
 */

var blobBuilderSupported = BlobBuilder
  && BlobBuilder.prototype.append
  && BlobBuilder.prototype.getBlob;

/**
 * Helper function that maps ArrayBufferViews to ArrayBuffers
 * Used by BlobBuilder constructor and old browsers that didn't
 * support it in the Blob constructor.
 */

function mapArrayBufferViews(ary) {
  return ary.map(function(chunk) {
    if (chunk.buffer instanceof ArrayBuffer) {
      var buf = chunk.buffer;

      // if this is a subarray, make a copy so we only
      // include the subarray region from the underlying buffer
      if (chunk.byteLength !== buf.byteLength) {
        var copy = new Uint8Array(chunk.byteLength);
        copy.set(new Uint8Array(buf, chunk.byteOffset, chunk.byteLength));
        buf = copy.buffer;
      }

      return buf;
    }

    return chunk;
  });
}

function BlobBuilderConstructor(ary, options) {
  options = options || {};

  var bb = new BlobBuilder();
  mapArrayBufferViews(ary).forEach(function(part) {
    bb.append(part);
  });

  return (options.type) ? bb.getBlob(options.type) : bb.getBlob();
};

function BlobConstructor(ary, options) {
  return new Blob(mapArrayBufferViews(ary), options || {});
};

if (typeof Blob !== 'undefined') {
  BlobBuilderConstructor.prototype = Blob.prototype;
  BlobConstructor.prototype = Blob.prototype;
}

module.exports = (function() {
  if (blobSupported) {
    return blobSupportsArrayBufferView ? Blob : BlobConstructor;
  } else if (blobBuilderSupported) {
    return BlobBuilderConstructor;
  } else {
    return undefined;
  }
})();

},{}],8:[function(require,module,exports){

},{}],9:[function(require,module,exports){
(function (Buffer){(function (){
/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <https://feross.org>
 * @license  MIT
 */
/* eslint-disable no-proto */

'use strict'

var base64 = require('base64-js')
var ieee754 = require('ieee754')

exports.Buffer = Buffer
exports.SlowBuffer = SlowBuffer
exports.INSPECT_MAX_BYTES = 50

var K_MAX_LENGTH = 0x7fffffff
exports.kMaxLength = K_MAX_LENGTH

/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Print warning and recommend using `buffer` v4.x which has an Object
 *               implementation (most compatible, even IE6)
 *
 * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
 * Opera 11.6+, iOS 4.2+.
 *
 * We report that the browser does not support typed arrays if the are not subclassable
 * using __proto__. Firefox 4-29 lacks support for adding new properties to `Uint8Array`
 * (See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438). IE 10 lacks support
 * for __proto__ and has a buggy typed array implementation.
 */
Buffer.TYPED_ARRAY_SUPPORT = typedArraySupport()

if (!Buffer.TYPED_ARRAY_SUPPORT && typeof console !== 'undefined' &&
    typeof console.error === 'function') {
  console.error(
    'This browser lacks typed array (Uint8Array) support which is required by ' +
    '`buffer` v5.x. Use `buffer` v4.x if you require old browser support.'
  )
}

function typedArraySupport () {
  // Can typed array instances can be augmented?
  try {
    var arr = new Uint8Array(1)
    arr.__proto__ = { __proto__: Uint8Array.prototype, foo: function () { return 42 } }
    return arr.foo() === 42
  } catch (e) {
    return false
  }
}

Object.defineProperty(Buffer.prototype, 'parent', {
  enumerable: true,
  get: function () {
    if (!Buffer.isBuffer(this)) return undefined
    return this.buffer
  }
})

Object.defineProperty(Buffer.prototype, 'offset', {
  enumerable: true,
  get: function () {
    if (!Buffer.isBuffer(this)) return undefined
    return this.byteOffset
  }
})

function createBuffer (length) {
  if (length > K_MAX_LENGTH) {
    throw new RangeError('The value "' + length + '" is invalid for option "size"')
  }
  // Return an augmented `Uint8Array` instance
  var buf = new Uint8Array(length)
  buf.__proto__ = Buffer.prototype
  return buf
}

/**
 * The Buffer constructor returns instances of `Uint8Array` that have their
 * prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
 * `Uint8Array`, so the returned instances will have all the node `Buffer` methods
 * and the `Uint8Array` methods. Square bracket notation works as expected -- it
 * returns a single octet.
 *
 * The `Uint8Array` prototype remains unmodified.
 */

function Buffer (arg, encodingOrOffset, length) {
  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new TypeError(
        'The "string" argument must be of type string. Received type number'
      )
    }
    return allocUnsafe(arg)
  }
  return from(arg, encodingOrOffset, length)
}

// Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
if (typeof Symbol !== 'undefined' && Symbol.species != null &&
    Buffer[Symbol.species] === Buffer) {
  Object.defineProperty(Buffer, Symbol.species, {
    value: null,
    configurable: true,
    enumerable: false,
    writable: false
  })
}

Buffer.poolSize = 8192 // not used by this implementation

function from (value, encodingOrOffset, length) {
  if (typeof value === 'string') {
    return fromString(value, encodingOrOffset)
  }

  if (ArrayBuffer.isView(value)) {
    return fromArrayLike(value)
  }

  if (value == null) {
    throw TypeError(
      'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
      'or Array-like Object. Received type ' + (typeof value)
    )
  }

  if (isInstance(value, ArrayBuffer) ||
      (value && isInstance(value.buffer, ArrayBuffer))) {
    return fromArrayBuffer(value, encodingOrOffset, length)
  }

  if (typeof value === 'number') {
    throw new TypeError(
      'The "value" argument must not be of type number. Received type number'
    )
  }

  var valueOf = value.valueOf && value.valueOf()
  if (valueOf != null && valueOf !== value) {
    return Buffer.from(valueOf, encodingOrOffset, length)
  }

  var b = fromObject(value)
  if (b) return b

  if (typeof Symbol !== 'undefined' && Symbol.toPrimitive != null &&
      typeof value[Symbol.toPrimitive] === 'function') {
    return Buffer.from(
      value[Symbol.toPrimitive]('string'), encodingOrOffset, length
    )
  }

  throw new TypeError(
    'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
    'or Array-like Object. Received type ' + (typeof value)
  )
}

/**
 * Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
 * if value is a number.
 * Buffer.from(str[, encoding])
 * Buffer.from(array)
 * Buffer.from(buffer)
 * Buffer.from(arrayBuffer[, byteOffset[, length]])
 **/
Buffer.from = function (value, encodingOrOffset, length) {
  return from(value, encodingOrOffset, length)
}

// Note: Change prototype *after* Buffer.from is defined to workaround Chrome bug:
// https://github.com/feross/buffer/pull/148
Buffer.prototype.__proto__ = Uint8Array.prototype
Buffer.__proto__ = Uint8Array

function assertSize (size) {
  if (typeof size !== 'number') {
    throw new TypeError('"size" argument must be of type number')
  } else if (size < 0) {
    throw new RangeError('The value "' + size + '" is invalid for option "size"')
  }
}

function alloc (size, fill, encoding) {
  assertSize(size)
  if (size <= 0) {
    return createBuffer(size)
  }
  if (fill !== undefined) {
    // Only pay attention to encoding if it's a string. This
    // prevents accidentally sending in a number that would
    // be interpretted as a start offset.
    return typeof encoding === 'string'
      ? createBuffer(size).fill(fill, encoding)
      : createBuffer(size).fill(fill)
  }
  return createBuffer(size)
}

/**
 * Creates a new filled Buffer instance.
 * alloc(size[, fill[, encoding]])
 **/
Buffer.alloc = function (size, fill, encoding) {
  return alloc(size, fill, encoding)
}

function allocUnsafe (size) {
  assertSize(size)
  return createBuffer(size < 0 ? 0 : checked(size) | 0)
}

/**
 * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
 * */
Buffer.allocUnsafe = function (size) {
  return allocUnsafe(size)
}
/**
 * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
 */
Buffer.allocUnsafeSlow = function (size) {
  return allocUnsafe(size)
}

function fromString (string, encoding) {
  if (typeof encoding !== 'string' || encoding === '') {
    encoding = 'utf8'
  }

  if (!Buffer.isEncoding(encoding)) {
    throw new TypeError('Unknown encoding: ' + encoding)
  }

  var length = byteLength(string, encoding) | 0
  var buf = createBuffer(length)

  var actual = buf.write(string, encoding)

  if (actual !== length) {
    // Writing a hex string, for example, that contains invalid characters will
    // cause everything after the first invalid character to be ignored. (e.g.
    // 'abxxcd' will be treated as 'ab')
    buf = buf.slice(0, actual)
  }

  return buf
}

function fromArrayLike (array) {
  var length = array.length < 0 ? 0 : checked(array.length) | 0
  var buf = createBuffer(length)
  for (var i = 0; i < length; i += 1) {
    buf[i] = array[i] & 255
  }
  return buf
}

function fromArrayBuffer (array, byteOffset, length) {
  if (byteOffset < 0 || array.byteLength < byteOffset) {
    throw new RangeError('"offset" is outside of buffer bounds')
  }

  if (array.byteLength < byteOffset + (length || 0)) {
    throw new RangeError('"length" is outside of buffer bounds')
  }

  var buf
  if (byteOffset === undefined && length === undefined) {
    buf = new Uint8Array(array)
  } else if (length === undefined) {
    buf = new Uint8Array(array, byteOffset)
  } else {
    buf = new Uint8Array(array, byteOffset, length)
  }

  // Return an augmented `Uint8Array` instance
  buf.__proto__ = Buffer.prototype
  return buf
}

function fromObject (obj) {
  if (Buffer.isBuffer(obj)) {
    var len = checked(obj.length) | 0
    var buf = createBuffer(len)

    if (buf.length === 0) {
      return buf
    }

    obj.copy(buf, 0, 0, len)
    return buf
  }

  if (obj.length !== undefined) {
    if (typeof obj.length !== 'number' || numberIsNaN(obj.length)) {
      return createBuffer(0)
    }
    return fromArrayLike(obj)
  }

  if (obj.type === 'Buffer' && Array.isArray(obj.data)) {
    return fromArrayLike(obj.data)
  }
}

function checked (length) {
  // Note: cannot use `length < K_MAX_LENGTH` here because that fails when
  // length is NaN (which is otherwise coerced to zero.)
  if (length >= K_MAX_LENGTH) {
    throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
                         'size: 0x' + K_MAX_LENGTH.toString(16) + ' bytes')
  }
  return length | 0
}

function SlowBuffer (length) {
  if (+length != length) { // eslint-disable-line eqeqeq
    length = 0
  }
  return Buffer.alloc(+length)
}

Buffer.isBuffer = function isBuffer (b) {
  return b != null && b._isBuffer === true &&
    b !== Buffer.prototype // so Buffer.isBuffer(Buffer.prototype) will be false
}

Buffer.compare = function compare (a, b) {
  if (isInstance(a, Uint8Array)) a = Buffer.from(a, a.offset, a.byteLength)
  if (isInstance(b, Uint8Array)) b = Buffer.from(b, b.offset, b.byteLength)
  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
    throw new TypeError(
      'The "buf1", "buf2" arguments must be one of type Buffer or Uint8Array'
    )
  }

  if (a === b) return 0

  var x = a.length
  var y = b.length

  for (var i = 0, len = Math.min(x, y); i < len; ++i) {
    if (a[i] !== b[i]) {
      x = a[i]
      y = b[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

Buffer.isEncoding = function isEncoding (encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'latin1':
    case 'binary':
    case 'base64':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true
    default:
      return false
  }
}

Buffer.concat = function concat (list, length) {
  if (!Array.isArray(list)) {
    throw new TypeError('"list" argument must be an Array of Buffers')
  }

  if (list.length === 0) {
    return Buffer.alloc(0)
  }

  var i
  if (length === undefined) {
    length = 0
    for (i = 0; i < list.length; ++i) {
      length += list[i].length
    }
  }

  var buffer = Buffer.allocUnsafe(length)
  var pos = 0
  for (i = 0; i < list.length; ++i) {
    var buf = list[i]
    if (isInstance(buf, Uint8Array)) {
      buf = Buffer.from(buf)
    }
    if (!Buffer.isBuffer(buf)) {
      throw new TypeError('"list" argument must be an Array of Buffers')
    }
    buf.copy(buffer, pos)
    pos += buf.length
  }
  return buffer
}

function byteLength (string, encoding) {
  if (Buffer.isBuffer(string)) {
    return string.length
  }
  if (ArrayBuffer.isView(string) || isInstance(string, ArrayBuffer)) {
    return string.byteLength
  }
  if (typeof string !== 'string') {
    throw new TypeError(
      'The "string" argument must be one of type string, Buffer, or ArrayBuffer. ' +
      'Received type ' + typeof string
    )
  }

  var len = string.length
  var mustMatch = (arguments.length > 2 && arguments[2] === true)
  if (!mustMatch && len === 0) return 0

  // Use a for loop to avoid recursion
  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'ascii':
      case 'latin1':
      case 'binary':
        return len
      case 'utf8':
      case 'utf-8':
        return utf8ToBytes(string).length
      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return len * 2
      case 'hex':
        return len >>> 1
      case 'base64':
        return base64ToBytes(string).length
      default:
        if (loweredCase) {
          return mustMatch ? -1 : utf8ToBytes(string).length // assume utf8
        }
        encoding = ('' + encoding).toLowerCase()
        loweredCase = true
    }
  }
}
Buffer.byteLength = byteLength

function slowToString (encoding, start, end) {
  var loweredCase = false

  // No need to verify that "this.length <= MAX_UINT32" since it's a read-only
  // property of a typed array.

  // This behaves neither like String nor Uint8Array in that we set start/end
  // to their upper/lower bounds if the value passed is out of range.
  // undefined is handled specially as per ECMA-262 6th Edition,
  // Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
  if (start === undefined || start < 0) {
    start = 0
  }
  // Return early if start > this.length. Done here to prevent potential uint32
  // coercion fail below.
  if (start > this.length) {
    return ''
  }

  if (end === undefined || end > this.length) {
    end = this.length
  }

  if (end <= 0) {
    return ''
  }

  // Force coersion to uint32. This will also coerce falsey/NaN values to 0.
  end >>>= 0
  start >>>= 0

  if (end <= start) {
    return ''
  }

  if (!encoding) encoding = 'utf8'

  while (true) {
    switch (encoding) {
      case 'hex':
        return hexSlice(this, start, end)

      case 'utf8':
      case 'utf-8':
        return utf8Slice(this, start, end)

      case 'ascii':
        return asciiSlice(this, start, end)

      case 'latin1':
      case 'binary':
        return latin1Slice(this, start, end)

      case 'base64':
        return base64Slice(this, start, end)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return utf16leSlice(this, start, end)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = (encoding + '').toLowerCase()
        loweredCase = true
    }
  }
}

// This property is used by `Buffer.isBuffer` (and the `is-buffer` npm package)
// to detect a Buffer instance. It's not possible to use `instanceof Buffer`
// reliably in a browserify context because there could be multiple different
// copies of the 'buffer' package in use. This method works even for Buffer
// instances that were created from another copy of the `buffer` package.
// See: https://github.com/feross/buffer/issues/154
Buffer.prototype._isBuffer = true

function swap (b, n, m) {
  var i = b[n]
  b[n] = b[m]
  b[m] = i
}

Buffer.prototype.swap16 = function swap16 () {
  var len = this.length
  if (len % 2 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 16-bits')
  }
  for (var i = 0; i < len; i += 2) {
    swap(this, i, i + 1)
  }
  return this
}

Buffer.prototype.swap32 = function swap32 () {
  var len = this.length
  if (len % 4 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 32-bits')
  }
  for (var i = 0; i < len; i += 4) {
    swap(this, i, i + 3)
    swap(this, i + 1, i + 2)
  }
  return this
}

Buffer.prototype.swap64 = function swap64 () {
  var len = this.length
  if (len % 8 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 64-bits')
  }
  for (var i = 0; i < len; i += 8) {
    swap(this, i, i + 7)
    swap(this, i + 1, i + 6)
    swap(this, i + 2, i + 5)
    swap(this, i + 3, i + 4)
  }
  return this
}

Buffer.prototype.toString = function toString () {
  var length = this.length
  if (length === 0) return ''
  if (arguments.length === 0) return utf8Slice(this, 0, length)
  return slowToString.apply(this, arguments)
}

Buffer.prototype.toLocaleString = Buffer.prototype.toString

Buffer.prototype.equals = function equals (b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
  if (this === b) return true
  return Buffer.compare(this, b) === 0
}

Buffer.prototype.inspect = function inspect () {
  var str = ''
  var max = exports.INSPECT_MAX_BYTES
  str = this.toString('hex', 0, max).replace(/(.{2})/g, '$1 ').trim()
  if (this.length > max) str += ' ... '
  return '<Buffer ' + str + '>'
}

Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
  if (isInstance(target, Uint8Array)) {
    target = Buffer.from(target, target.offset, target.byteLength)
  }
  if (!Buffer.isBuffer(target)) {
    throw new TypeError(
      'The "target" argument must be one of type Buffer or Uint8Array. ' +
      'Received type ' + (typeof target)
    )
  }

  if (start === undefined) {
    start = 0
  }
  if (end === undefined) {
    end = target ? target.length : 0
  }
  if (thisStart === undefined) {
    thisStart = 0
  }
  if (thisEnd === undefined) {
    thisEnd = this.length
  }

  if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
    throw new RangeError('out of range index')
  }

  if (thisStart >= thisEnd && start >= end) {
    return 0
  }
  if (thisStart >= thisEnd) {
    return -1
  }
  if (start >= end) {
    return 1
  }

  start >>>= 0
  end >>>= 0
  thisStart >>>= 0
  thisEnd >>>= 0

  if (this === target) return 0

  var x = thisEnd - thisStart
  var y = end - start
  var len = Math.min(x, y)

  var thisCopy = this.slice(thisStart, thisEnd)
  var targetCopy = target.slice(start, end)

  for (var i = 0; i < len; ++i) {
    if (thisCopy[i] !== targetCopy[i]) {
      x = thisCopy[i]
      y = targetCopy[i]
      break
    }
  }

  if (x < y) return -1
  if (y < x) return 1
  return 0
}

// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
  // Empty buffer means no match
  if (buffer.length === 0) return -1

  // Normalize byteOffset
  if (typeof byteOffset === 'string') {
    encoding = byteOffset
    byteOffset = 0
  } else if (byteOffset > 0x7fffffff) {
    byteOffset = 0x7fffffff
  } else if (byteOffset < -0x80000000) {
    byteOffset = -0x80000000
  }
  byteOffset = +byteOffset // Coerce to Number.
  if (numberIsNaN(byteOffset)) {
    // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
    byteOffset = dir ? 0 : (buffer.length - 1)
  }

  // Normalize byteOffset: negative offsets start from the end of the buffer
  if (byteOffset < 0) byteOffset = buffer.length + byteOffset
  if (byteOffset >= buffer.length) {
    if (dir) return -1
    else byteOffset = buffer.length - 1
  } else if (byteOffset < 0) {
    if (dir) byteOffset = 0
    else return -1
  }

  // Normalize val
  if (typeof val === 'string') {
    val = Buffer.from(val, encoding)
  }

  // Finally, search either indexOf (if dir is true) or lastIndexOf
  if (Buffer.isBuffer(val)) {
    // Special case: looking for empty string/buffer always fails
    if (val.length === 0) {
      return -1
    }
    return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
  } else if (typeof val === 'number') {
    val = val & 0xFF // Search for a byte value [0-255]
    if (typeof Uint8Array.prototype.indexOf === 'function') {
      if (dir) {
        return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
      } else {
        return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset)
      }
    }
    return arrayIndexOf(buffer, [ val ], byteOffset, encoding, dir)
  }

  throw new TypeError('val must be string, number or Buffer')
}

function arrayIndexOf (arr, val, byteOffset, encoding, dir) {
  var indexSize = 1
  var arrLength = arr.length
  var valLength = val.length

  if (encoding !== undefined) {
    encoding = String(encoding).toLowerCase()
    if (encoding === 'ucs2' || encoding === 'ucs-2' ||
        encoding === 'utf16le' || encoding === 'utf-16le') {
      if (arr.length < 2 || val.length < 2) {
        return -1
      }
      indexSize = 2
      arrLength /= 2
      valLength /= 2
      byteOffset /= 2
    }
  }

  function read (buf, i) {
    if (indexSize === 1) {
      return buf[i]
    } else {
      return buf.readUInt16BE(i * indexSize)
    }
  }

  var i
  if (dir) {
    var foundIndex = -1
    for (i = byteOffset; i < arrLength; i++) {
      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
        if (foundIndex === -1) foundIndex = i
        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize
      } else {
        if (foundIndex !== -1) i -= i - foundIndex
        foundIndex = -1
      }
    }
  } else {
    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength
    for (i = byteOffset; i >= 0; i--) {
      var found = true
      for (var j = 0; j < valLength; j++) {
        if (read(arr, i + j) !== read(val, j)) {
          found = false
          break
        }
      }
      if (found) return i
    }
  }

  return -1
}

Buffer.prototype.includes = function includes (val, byteOffset, encoding) {
  return this.indexOf(val, byteOffset, encoding) !== -1
}

Buffer.prototype.indexOf = function indexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, true)
}

Buffer.prototype.lastIndexOf = function lastIndexOf (val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, false)
}

function hexWrite (buf, string, offset, length) {
  offset = Number(offset) || 0
  var remaining = buf.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }

  var strLen = string.length

  if (length > strLen / 2) {
    length = strLen / 2
  }
  for (var i = 0; i < length; ++i) {
    var parsed = parseInt(string.substr(i * 2, 2), 16)
    if (numberIsNaN(parsed)) return i
    buf[offset + i] = parsed
  }
  return i
}

function utf8Write (buf, string, offset, length) {
  return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
}

function asciiWrite (buf, string, offset, length) {
  return blitBuffer(asciiToBytes(string), buf, offset, length)
}

function latin1Write (buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length)
}

function base64Write (buf, string, offset, length) {
  return blitBuffer(base64ToBytes(string), buf, offset, length)
}

function ucs2Write (buf, string, offset, length) {
  return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
}

Buffer.prototype.write = function write (string, offset, length, encoding) {
  // Buffer#write(string)
  if (offset === undefined) {
    encoding = 'utf8'
    length = this.length
    offset = 0
  // Buffer#write(string, encoding)
  } else if (length === undefined && typeof offset === 'string') {
    encoding = offset
    length = this.length
    offset = 0
  // Buffer#write(string, offset[, length][, encoding])
  } else if (isFinite(offset)) {
    offset = offset >>> 0
    if (isFinite(length)) {
      length = length >>> 0
      if (encoding === undefined) encoding = 'utf8'
    } else {
      encoding = length
      length = undefined
    }
  } else {
    throw new Error(
      'Buffer.write(string, encoding, offset[, length]) is no longer supported'
    )
  }

  var remaining = this.length - offset
  if (length === undefined || length > remaining) length = remaining

  if ((string.length > 0 && (length < 0 || offset < 0)) || offset > this.length) {
    throw new RangeError('Attempt to write outside buffer bounds')
  }

  if (!encoding) encoding = 'utf8'

  var loweredCase = false
  for (;;) {
    switch (encoding) {
      case 'hex':
        return hexWrite(this, string, offset, length)

      case 'utf8':
      case 'utf-8':
        return utf8Write(this, string, offset, length)

      case 'ascii':
        return asciiWrite(this, string, offset, length)

      case 'latin1':
      case 'binary':
        return latin1Write(this, string, offset, length)

      case 'base64':
        // Warning: maxLength not taken into account in base64Write
        return base64Write(this, string, offset, length)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return ucs2Write(this, string, offset, length)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = ('' + encoding).toLowerCase()
        loweredCase = true
    }
  }
}

Buffer.prototype.toJSON = function toJSON () {
  return {
    type: 'Buffer',
    data: Array.prototype.slice.call(this._arr || this, 0)
  }
}

function base64Slice (buf, start, end) {
  if (start === 0 && end === buf.length) {
    return base64.fromByteArray(buf)
  } else {
    return base64.fromByteArray(buf.slice(start, end))
  }
}

function utf8Slice (buf, start, end) {
  end = Math.min(buf.length, end)
  var res = []

  var i = start
  while (i < end) {
    var firstByte = buf[i]
    var codePoint = null
    var bytesPerSequence = (firstByte > 0xEF) ? 4
      : (firstByte > 0xDF) ? 3
        : (firstByte > 0xBF) ? 2
          : 1

    if (i + bytesPerSequence <= end) {
      var secondByte, thirdByte, fourthByte, tempCodePoint

      switch (bytesPerSequence) {
        case 1:
          if (firstByte < 0x80) {
            codePoint = firstByte
          }
          break
        case 2:
          secondByte = buf[i + 1]
          if ((secondByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0x1F) << 0x6 | (secondByte & 0x3F)
            if (tempCodePoint > 0x7F) {
              codePoint = tempCodePoint
            }
          }
          break
        case 3:
          secondByte = buf[i + 1]
          thirdByte = buf[i + 2]
          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | (thirdByte & 0x3F)
            if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
              codePoint = tempCodePoint
            }
          }
          break
        case 4:
          secondByte = buf[i + 1]
          thirdByte = buf[i + 2]
          fourthByte = buf[i + 3]
          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80 && (fourthByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0x12 | (secondByte & 0x3F) << 0xC | (thirdByte & 0x3F) << 0x6 | (fourthByte & 0x3F)
            if (tempCodePoint > 0xFFFF && tempCodePoint < 0x110000) {
              codePoint = tempCodePoint
            }
          }
      }
    }

    if (codePoint === null) {
      // we did not generate a valid codePoint so insert a
      // replacement char (U+FFFD) and advance only 1 byte
      codePoint = 0xFFFD
      bytesPerSequence = 1
    } else if (codePoint > 0xFFFF) {
      // encode to utf16 (surrogate pair dance)
      codePoint -= 0x10000
      res.push(codePoint >>> 10 & 0x3FF | 0xD800)
      codePoint = 0xDC00 | codePoint & 0x3FF
    }

    res.push(codePoint)
    i += bytesPerSequence
  }

  return decodeCodePointsArray(res)
}

// Based on http://stackoverflow.com/a/22747272/680742, the browser with
// the lowest limit is Chrome, with 0x10000 args.
// We go 1 magnitude less, for safety
var MAX_ARGUMENTS_LENGTH = 0x1000

function decodeCodePointsArray (codePoints) {
  var len = codePoints.length
  if (len <= MAX_ARGUMENTS_LENGTH) {
    return String.fromCharCode.apply(String, codePoints) // avoid extra slice()
  }

  // Decode in chunks to avoid "call stack size exceeded".
  var res = ''
  var i = 0
  while (i < len) {
    res += String.fromCharCode.apply(
      String,
      codePoints.slice(i, i += MAX_ARGUMENTS_LENGTH)
    )
  }
  return res
}

function asciiSlice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i] & 0x7F)
  }
  return ret
}

function latin1Slice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i])
  }
  return ret
}

function hexSlice (buf, start, end) {
  var len = buf.length

  if (!start || start < 0) start = 0
  if (!end || end < 0 || end > len) end = len

  var out = ''
  for (var i = start; i < end; ++i) {
    out += toHex(buf[i])
  }
  return out
}

function utf16leSlice (buf, start, end) {
  var bytes = buf.slice(start, end)
  var res = ''
  for (var i = 0; i < bytes.length; i += 2) {
    res += String.fromCharCode(bytes[i] + (bytes[i + 1] * 256))
  }
  return res
}

Buffer.prototype.slice = function slice (start, end) {
  var len = this.length
  start = ~~start
  end = end === undefined ? len : ~~end

  if (start < 0) {
    start += len
    if (start < 0) start = 0
  } else if (start > len) {
    start = len
  }

  if (end < 0) {
    end += len
    if (end < 0) end = 0
  } else if (end > len) {
    end = len
  }

  if (end < start) end = start

  var newBuf = this.subarray(start, end)
  // Return an augmented `Uint8Array` instance
  newBuf.__proto__ = Buffer.prototype
  return newBuf
}

/*
 * Need to make sure that buffer isn't trying to write out of bounds.
 */
function checkOffset (offset, ext, length) {
  if ((offset % 1) !== 0 || offset < 0) throw new RangeError('offset is not uint')
  if (offset + ext > length) throw new RangeError('Trying to access beyond buffer length')
}

Buffer.prototype.readUIntLE = function readUIntLE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }

  return val
}

Buffer.prototype.readUIntBE = function readUIntBE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) {
    checkOffset(offset, byteLength, this.length)
  }

  var val = this[offset + --byteLength]
  var mul = 1
  while (byteLength > 0 && (mul *= 0x100)) {
    val += this[offset + --byteLength] * mul
  }

  return val
}

Buffer.prototype.readUInt8 = function readUInt8 (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 1, this.length)
  return this[offset]
}

Buffer.prototype.readUInt16LE = function readUInt16LE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 2, this.length)
  return this[offset] | (this[offset + 1] << 8)
}

Buffer.prototype.readUInt16BE = function readUInt16BE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 2, this.length)
  return (this[offset] << 8) | this[offset + 1]
}

Buffer.prototype.readUInt32LE = function readUInt32LE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)

  return ((this[offset]) |
      (this[offset + 1] << 8) |
      (this[offset + 2] << 16)) +
      (this[offset + 3] * 0x1000000)
}

Buffer.prototype.readUInt32BE = function readUInt32BE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] * 0x1000000) +
    ((this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    this[offset + 3])
}

Buffer.prototype.readIntLE = function readIntLE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readIntBE = function readIntBE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var i = byteLength
  var mul = 1
  var val = this[offset + --i]
  while (i > 0 && (mul *= 0x100)) {
    val += this[offset + --i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readInt8 = function readInt8 (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 1, this.length)
  if (!(this[offset] & 0x80)) return (this[offset])
  return ((0xff - this[offset] + 1) * -1)
}

Buffer.prototype.readInt16LE = function readInt16LE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset] | (this[offset + 1] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt16BE = function readInt16BE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset + 1] | (this[offset] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt32LE = function readInt32LE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset]) |
    (this[offset + 1] << 8) |
    (this[offset + 2] << 16) |
    (this[offset + 3] << 24)
}

Buffer.prototype.readInt32BE = function readInt32BE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] << 24) |
    (this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    (this[offset + 3])
}

Buffer.prototype.readFloatLE = function readFloatLE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, true, 23, 4)
}

Buffer.prototype.readFloatBE = function readFloatBE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, false, 23, 4)
}

Buffer.prototype.readDoubleLE = function readDoubleLE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, true, 52, 8)
}

Buffer.prototype.readDoubleBE = function readDoubleBE (offset, noAssert) {
  offset = offset >>> 0
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, false, 52, 8)
}

function checkInt (buf, value, offset, ext, max, min) {
  if (!Buffer.isBuffer(buf)) throw new TypeError('"buffer" argument must be a Buffer instance')
  if (value > max || value < min) throw new RangeError('"value" argument is out of bounds')
  if (offset + ext > buf.length) throw new RangeError('Index out of range')
}

Buffer.prototype.writeUIntLE = function writeUIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1
    checkInt(this, value, offset, byteLength, maxBytes, 0)
  }

  var mul = 1
  var i = 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    this[offset + i] = (value / mul) & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUIntBE = function writeUIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1
    checkInt(this, value, offset, byteLength, maxBytes, 0)
  }

  var i = byteLength - 1
  var mul = 1
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    this[offset + i] = (value / mul) & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
  this[offset] = (value & 0xff)
  return offset + 1
}

Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  this[offset] = (value & 0xff)
  this[offset + 1] = (value >>> 8)
  return offset + 2
}

Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  this[offset] = (value >>> 8)
  this[offset + 1] = (value & 0xff)
  return offset + 2
}

Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  this[offset + 3] = (value >>> 24)
  this[offset + 2] = (value >>> 16)
  this[offset + 1] = (value >>> 8)
  this[offset] = (value & 0xff)
  return offset + 4
}

Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  this[offset] = (value >>> 24)
  this[offset + 1] = (value >>> 16)
  this[offset + 2] = (value >>> 8)
  this[offset + 3] = (value & 0xff)
  return offset + 4
}

Buffer.prototype.writeIntLE = function writeIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    var limit = Math.pow(2, (8 * byteLength) - 1)

    checkInt(this, value, offset, byteLength, limit - 1, -limit)
  }

  var i = 0
  var mul = 1
  var sub = 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i - 1] !== 0) {
      sub = 1
    }
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeIntBE = function writeIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    var limit = Math.pow(2, (8 * byteLength) - 1)

    checkInt(this, value, offset, byteLength, limit - 1, -limit)
  }

  var i = byteLength - 1
  var mul = 1
  var sub = 0
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i + 1] !== 0) {
      sub = 1
    }
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
  if (value < 0) value = 0xff + value + 1
  this[offset] = (value & 0xff)
  return offset + 1
}

Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  this[offset] = (value & 0xff)
  this[offset + 1] = (value >>> 8)
  return offset + 2
}

Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  this[offset] = (value >>> 8)
  this[offset + 1] = (value & 0xff)
  return offset + 2
}

Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  this[offset] = (value & 0xff)
  this[offset + 1] = (value >>> 8)
  this[offset + 2] = (value >>> 16)
  this[offset + 3] = (value >>> 24)
  return offset + 4
}

Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  if (value < 0) value = 0xffffffff + value + 1
  this[offset] = (value >>> 24)
  this[offset + 1] = (value >>> 16)
  this[offset + 2] = (value >>> 8)
  this[offset + 3] = (value & 0xff)
  return offset + 4
}

function checkIEEE754 (buf, value, offset, ext, max, min) {
  if (offset + ext > buf.length) throw new RangeError('Index out of range')
  if (offset < 0) throw new RangeError('Index out of range')
}

function writeFloat (buf, value, offset, littleEndian, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 4, 3.4028234663852886e+38, -3.4028234663852886e+38)
  }
  ieee754.write(buf, value, offset, littleEndian, 23, 4)
  return offset + 4
}

Buffer.prototype.writeFloatLE = function writeFloatLE (value, offset, noAssert) {
  return writeFloat(this, value, offset, true, noAssert)
}

Buffer.prototype.writeFloatBE = function writeFloatBE (value, offset, noAssert) {
  return writeFloat(this, value, offset, false, noAssert)
}

function writeDouble (buf, value, offset, littleEndian, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 8, 1.7976931348623157E+308, -1.7976931348623157E+308)
  }
  ieee754.write(buf, value, offset, littleEndian, 52, 8)
  return offset + 8
}

Buffer.prototype.writeDoubleLE = function writeDoubleLE (value, offset, noAssert) {
  return writeDouble(this, value, offset, true, noAssert)
}

Buffer.prototype.writeDoubleBE = function writeDoubleBE (value, offset, noAssert) {
  return writeDouble(this, value, offset, false, noAssert)
}

// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
Buffer.prototype.copy = function copy (target, targetStart, start, end) {
  if (!Buffer.isBuffer(target)) throw new TypeError('argument should be a Buffer')
  if (!start) start = 0
  if (!end && end !== 0) end = this.length
  if (targetStart >= target.length) targetStart = target.length
  if (!targetStart) targetStart = 0
  if (end > 0 && end < start) end = start

  // Copy 0 bytes; we're done
  if (end === start) return 0
  if (target.length === 0 || this.length === 0) return 0

  // Fatal error conditions
  if (targetStart < 0) {
    throw new RangeError('targetStart out of bounds')
  }
  if (start < 0 || start >= this.length) throw new RangeError('Index out of range')
  if (end < 0) throw new RangeError('sourceEnd out of bounds')

  // Are we oob?
  if (end > this.length) end = this.length
  if (target.length - targetStart < end - start) {
    end = target.length - targetStart + start
  }

  var len = end - start

  if (this === target && typeof Uint8Array.prototype.copyWithin === 'function') {
    // Use built-in when available, missing from IE11
    this.copyWithin(targetStart, start, end)
  } else if (this === target && start < targetStart && targetStart < end) {
    // descending copy from end
    for (var i = len - 1; i >= 0; --i) {
      target[i + targetStart] = this[i + start]
    }
  } else {
    Uint8Array.prototype.set.call(
      target,
      this.subarray(start, end),
      targetStart
    )
  }

  return len
}

// Usage:
//    buffer.fill(number[, offset[, end]])
//    buffer.fill(buffer[, offset[, end]])
//    buffer.fill(string[, offset[, end]][, encoding])
Buffer.prototype.fill = function fill (val, start, end, encoding) {
  // Handle string cases:
  if (typeof val === 'string') {
    if (typeof start === 'string') {
      encoding = start
      start = 0
      end = this.length
    } else if (typeof end === 'string') {
      encoding = end
      end = this.length
    }
    if (encoding !== undefined && typeof encoding !== 'string') {
      throw new TypeError('encoding must be a string')
    }
    if (typeof encoding === 'string' && !Buffer.isEncoding(encoding)) {
      throw new TypeError('Unknown encoding: ' + encoding)
    }
    if (val.length === 1) {
      var code = val.charCodeAt(0)
      if ((encoding === 'utf8' && code < 128) ||
          encoding === 'latin1') {
        // Fast path: If `val` fits into a single byte, use that numeric value.
        val = code
      }
    }
  } else if (typeof val === 'number') {
    val = val & 255
  }

  // Invalid ranges are not set to a default, so can range check early.
  if (start < 0 || this.length < start || this.length < end) {
    throw new RangeError('Out of range index')
  }

  if (end <= start) {
    return this
  }

  start = start >>> 0
  end = end === undefined ? this.length : end >>> 0

  if (!val) val = 0

  var i
  if (typeof val === 'number') {
    for (i = start; i < end; ++i) {
      this[i] = val
    }
  } else {
    var bytes = Buffer.isBuffer(val)
      ? val
      : Buffer.from(val, encoding)
    var len = bytes.length
    if (len === 0) {
      throw new TypeError('The value "' + val +
        '" is invalid for argument "value"')
    }
    for (i = 0; i < end - start; ++i) {
      this[i + start] = bytes[i % len]
    }
  }

  return this
}

// HELPER FUNCTIONS
// ================

var INVALID_BASE64_RE = /[^+/0-9A-Za-z-_]/g

function base64clean (str) {
  // Node takes equal signs as end of the Base64 encoding
  str = str.split('=')[0]
  // Node strips out invalid characters like \n and \t from the string, base64-js does not
  str = str.trim().replace(INVALID_BASE64_RE, '')
  // Node converts strings with length < 2 to ''
  if (str.length < 2) return ''
  // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not
  while (str.length % 4 !== 0) {
    str = str + '='
  }
  return str
}

function toHex (n) {
  if (n < 16) return '0' + n.toString(16)
  return n.toString(16)
}

function utf8ToBytes (string, units) {
  units = units || Infinity
  var codePoint
  var length = string.length
  var leadSurrogate = null
  var bytes = []

  for (var i = 0; i < length; ++i) {
    codePoint = string.charCodeAt(i)

    // is surrogate component
    if (codePoint > 0xD7FF && codePoint < 0xE000) {
      // last char was a lead
      if (!leadSurrogate) {
        // no lead yet
        if (codePoint > 0xDBFF) {
          // unexpected trail
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        } else if (i + 1 === length) {
          // unpaired lead
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        }

        // valid lead
        leadSurrogate = codePoint

        continue
      }

      // 2 leads in a row
      if (codePoint < 0xDC00) {
        if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
        leadSurrogate = codePoint
        continue
      }

      // valid surrogate pair
      codePoint = (leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00) + 0x10000
    } else if (leadSurrogate) {
      // valid bmp char, but last char was a lead
      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
    }

    leadSurrogate = null

    // encode utf8
    if (codePoint < 0x80) {
      if ((units -= 1) < 0) break
      bytes.push(codePoint)
    } else if (codePoint < 0x800) {
      if ((units -= 2) < 0) break
      bytes.push(
        codePoint >> 0x6 | 0xC0,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x10000) {
      if ((units -= 3) < 0) break
      bytes.push(
        codePoint >> 0xC | 0xE0,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x110000) {
      if ((units -= 4) < 0) break
      bytes.push(
        codePoint >> 0x12 | 0xF0,
        codePoint >> 0xC & 0x3F | 0x80,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else {
      throw new Error('Invalid code point')
    }
  }

  return bytes
}

function asciiToBytes (str) {
  var byteArray = []
  for (var i = 0; i < str.length; ++i) {
    // Node's code seems to be doing this and not & 0x7F..
    byteArray.push(str.charCodeAt(i) & 0xFF)
  }
  return byteArray
}

function utf16leToBytes (str, units) {
  var c, hi, lo
  var byteArray = []
  for (var i = 0; i < str.length; ++i) {
    if ((units -= 2) < 0) break

    c = str.charCodeAt(i)
    hi = c >> 8
    lo = c % 256
    byteArray.push(lo)
    byteArray.push(hi)
  }

  return byteArray
}

function base64ToBytes (str) {
  return base64.toByteArray(base64clean(str))
}

function blitBuffer (src, dst, offset, length) {
  for (var i = 0; i < length; ++i) {
    if ((i + offset >= dst.length) || (i >= src.length)) break
    dst[i + offset] = src[i]
  }
  return i
}

// ArrayBuffer or Uint8Array objects from other contexts (i.e. iframes) do not pass
// the `instanceof` check but they should be treated as of that type.
// See: https://github.com/feross/buffer/issues/166
function isInstance (obj, type) {
  return obj instanceof type ||
    (obj != null && obj.constructor != null && obj.constructor.name != null &&
      obj.constructor.name === type.name)
}
function numberIsNaN (obj) {
  // For IE11 support
  return obj !== obj // eslint-disable-line no-self-compare
}

}).call(this)}).call(this,require("buffer").Buffer)
},{"base64-js":6,"buffer":9,"ieee754":34}],10:[function(require,module,exports){
/**
 * Slice reference.
 */

var slice = [].slice;

/**
 * Bind `obj` to `fn`.
 *
 * @param {Object} obj
 * @param {Function|String} fn or string
 * @return {Function}
 * @api public
 */

module.exports = function(obj, fn){
  if ('string' == typeof fn) fn = obj[fn];
  if ('function' != typeof fn) throw new Error('bind() requires a function');
  var args = slice.call(arguments, 2);
  return function(){
    return fn.apply(obj, args.concat(slice.call(arguments)));
  }
};

},{}],11:[function(require,module,exports){

/**
 * Expose `Emitter`.
 */

if (typeof module !== 'undefined') {
  module.exports = Emitter;
}

/**
 * Initialize a new `Emitter`.
 *
 * @api public
 */

function Emitter(obj) {
  if (obj) return mixin(obj);
};

/**
 * Mixin the emitter properties.
 *
 * @param {Object} obj
 * @return {Object}
 * @api private
 */

function mixin(obj) {
  for (var key in Emitter.prototype) {
    obj[key] = Emitter.prototype[key];
  }
  return obj;
}

/**
 * Listen on the given `event` with `fn`.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.on =
Emitter.prototype.addEventListener = function(event, fn){
  this._callbacks = this._callbacks || {};
  (this._callbacks['$' + event] = this._callbacks['$' + event] || [])
    .push(fn);
  return this;
};

/**
 * Adds an `event` listener that will be invoked a single
 * time then automatically removed.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.once = function(event, fn){
  function on() {
    this.off(event, on);
    fn.apply(this, arguments);
  }

  on.fn = fn;
  this.on(event, on);
  return this;
};

/**
 * Remove the given callback for `event` or all
 * registered callbacks.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.off =
Emitter.prototype.removeListener =
Emitter.prototype.removeAllListeners =
Emitter.prototype.removeEventListener = function(event, fn){
  this._callbacks = this._callbacks || {};

  // all
  if (0 == arguments.length) {
    this._callbacks = {};
    return this;
  }

  // specific event
  var callbacks = this._callbacks['$' + event];
  if (!callbacks) return this;

  // remove all handlers
  if (1 == arguments.length) {
    delete this._callbacks['$' + event];
    return this;
  }

  // remove specific handler
  var cb;
  for (var i = 0; i < callbacks.length; i++) {
    cb = callbacks[i];
    if (cb === fn || cb.fn === fn) {
      callbacks.splice(i, 1);
      break;
    }
  }
  return this;
};

/**
 * Emit `event` with the given args.
 *
 * @param {String} event
 * @param {Mixed} ...
 * @return {Emitter}
 */

Emitter.prototype.emit = function(event){
  this._callbacks = this._callbacks || {};
  var args = [].slice.call(arguments, 1)
    , callbacks = this._callbacks['$' + event];

  if (callbacks) {
    callbacks = callbacks.slice(0);
    for (var i = 0, len = callbacks.length; i < len; ++i) {
      callbacks[i].apply(this, args);
    }
  }

  return this;
};

/**
 * Return array of callbacks for `event`.
 *
 * @param {String} event
 * @return {Array}
 * @api public
 */

Emitter.prototype.listeners = function(event){
  this._callbacks = this._callbacks || {};
  return this._callbacks['$' + event] || [];
};

/**
 * Check if this emitter has `event` handlers.
 *
 * @param {String} event
 * @return {Boolean}
 * @api public
 */

Emitter.prototype.hasListeners = function(event){
  return !! this.listeners(event).length;
};

},{}],12:[function(require,module,exports){

module.exports = function(a, b){
  var fn = function(){};
  fn.prototype = b.prototype;
  a.prototype = new fn;
  a.prototype.constructor = a;
};
},{}],13:[function(require,module,exports){
module.exports = (function () {
  if (typeof self !== 'undefined') {
    return self;
  } else if (typeof window !== 'undefined') {
    return window;
  } else {
    return Function('return this')(); // eslint-disable-line no-new-func
  }
})();

},{}],14:[function(require,module,exports){

module.exports = require('./socket');

/**
 * Exports parser
 *
 * @api public
 *
 */
module.exports.parser = require('engine.io-parser');

},{"./socket":15,"engine.io-parser":27}],15:[function(require,module,exports){
/**
 * Module dependencies.
 */

var transports = require('./transports/index');
var Emitter = require('component-emitter');
var debug = require('debug')('engine.io-client:socket');
var index = require('indexof');
var parser = require('engine.io-parser');
var parseuri = require('parseuri');
var parseqs = require('parseqs');

/**
 * Module exports.
 */

module.exports = Socket;

/**
 * Socket constructor.
 *
 * @param {String|Object} uri or options
 * @param {Object} options
 * @api public
 */

function Socket (uri, opts) {
  if (!(this instanceof Socket)) return new Socket(uri, opts);

  opts = opts || {};

  if (uri && 'object' === typeof uri) {
    opts = uri;
    uri = null;
  }

  if (uri) {
    uri = parseuri(uri);
    opts.hostname = uri.host;
    opts.secure = uri.protocol === 'https' || uri.protocol === 'wss';
    opts.port = uri.port;
    if (uri.query) opts.query = uri.query;
  } else if (opts.host) {
    opts.hostname = parseuri(opts.host).host;
  }

  this.secure = null != opts.secure ? opts.secure
    : (typeof location !== 'undefined' && 'https:' === location.protocol);

  if (opts.hostname && !opts.port) {
    // if no port is specified manually, use the protocol default
    opts.port = this.secure ? '443' : '80';
  }

  this.agent = opts.agent || false;
  this.hostname = opts.hostname ||
    (typeof location !== 'undefined' ? location.hostname : 'localhost');
  this.port = opts.port || (typeof location !== 'undefined' && location.port
      ? location.port
      : (this.secure ? 443 : 80));
  this.query = opts.query || {};
  if ('string' === typeof this.query) this.query = parseqs.decode(this.query);
  this.upgrade = false !== opts.upgrade;
  this.path = (opts.path || '/engine.io').replace(/\/$/, '') + '/';
  this.forceJSONP = !!opts.forceJSONP;
  this.jsonp = false !== opts.jsonp;
  this.forceBase64 = !!opts.forceBase64;
  this.enablesXDR = !!opts.enablesXDR;
  this.withCredentials = false !== opts.withCredentials;
  this.timestampParam = opts.timestampParam || 't';
  this.timestampRequests = opts.timestampRequests;
  this.transports = opts.transports || ['polling', 'websocket'];
  this.transportOptions = opts.transportOptions || {};
  this.readyState = '';
  this.writeBuffer = [];
  this.prevBufferLen = 0;
  this.policyPort = opts.policyPort || 843;
  this.rememberUpgrade = opts.rememberUpgrade || false;
  this.binaryType = null;
  this.onlyBinaryUpgrades = opts.onlyBinaryUpgrades;
  this.perMessageDeflate = false !== opts.perMessageDeflate ? (opts.perMessageDeflate || {}) : false;

  if (true === this.perMessageDeflate) this.perMessageDeflate = {};
  if (this.perMessageDeflate && null == this.perMessageDeflate.threshold) {
    this.perMessageDeflate.threshold = 1024;
  }

  // SSL options for Node.js client
  this.pfx = opts.pfx || null;
  this.key = opts.key || null;
  this.passphrase = opts.passphrase || null;
  this.cert = opts.cert || null;
  this.ca = opts.ca || null;
  this.ciphers = opts.ciphers || null;
  this.rejectUnauthorized = opts.rejectUnauthorized === undefined ? true : opts.rejectUnauthorized;
  this.forceNode = !!opts.forceNode;

  // detect ReactNative environment
  this.isReactNative = (typeof navigator !== 'undefined' && typeof navigator.product === 'string' && navigator.product.toLowerCase() === 'reactnative');

  // other options for Node.js or ReactNative client
  if (typeof self === 'undefined' || this.isReactNative) {
    if (opts.extraHeaders && Object.keys(opts.extraHeaders).length > 0) {
      this.extraHeaders = opts.extraHeaders;
    }

    if (opts.localAddress) {
      this.localAddress = opts.localAddress;
    }
  }

  // set on handshake
  this.id = null;
  this.upgrades = null;
  this.pingInterval = null;
  this.pingTimeout = null;

  // set on heartbeat
  this.pingIntervalTimer = null;
  this.pingTimeoutTimer = null;

  this.open();
}

Socket.priorWebsocketSuccess = false;

/**
 * Mix in `Emitter`.
 */

Emitter(Socket.prototype);

/**
 * Protocol version.
 *
 * @api public
 */

Socket.protocol = parser.protocol; // this is an int

/**
 * Expose deps for legacy compatibility
 * and standalone browser access.
 */

Socket.Socket = Socket;
Socket.Transport = require('./transport');
Socket.transports = require('./transports/index');
Socket.parser = require('engine.io-parser');

/**
 * Creates transport of the given type.
 *
 * @param {String} transport name
 * @return {Transport}
 * @api private
 */

Socket.prototype.createTransport = function (name) {
  debug('creating transport "%s"', name);
  var query = clone(this.query);

  // append engine.io protocol identifier
  query.EIO = parser.protocol;

  // transport name
  query.transport = name;

  // per-transport options
  var options = this.transportOptions[name] || {};

  // session id if we already have one
  if (this.id) query.sid = this.id;

  var transport = new transports[name]({
    query: query,
    socket: this,
    agent: options.agent || this.agent,
    hostname: options.hostname || this.hostname,
    port: options.port || this.port,
    secure: options.secure || this.secure,
    path: options.path || this.path,
    forceJSONP: options.forceJSONP || this.forceJSONP,
    jsonp: options.jsonp || this.jsonp,
    forceBase64: options.forceBase64 || this.forceBase64,
    enablesXDR: options.enablesXDR || this.enablesXDR,
    withCredentials: options.withCredentials || this.withCredentials,
    timestampRequests: options.timestampRequests || this.timestampRequests,
    timestampParam: options.timestampParam || this.timestampParam,
    policyPort: options.policyPort || this.policyPort,
    pfx: options.pfx || this.pfx,
    key: options.key || this.key,
    passphrase: options.passphrase || this.passphrase,
    cert: options.cert || this.cert,
    ca: options.ca || this.ca,
    ciphers: options.ciphers || this.ciphers,
    rejectUnauthorized: options.rejectUnauthorized || this.rejectUnauthorized,
    perMessageDeflate: options.perMessageDeflate || this.perMessageDeflate,
    extraHeaders: options.extraHeaders || this.extraHeaders,
    forceNode: options.forceNode || this.forceNode,
    localAddress: options.localAddress || this.localAddress,
    requestTimeout: options.requestTimeout || this.requestTimeout,
    protocols: options.protocols || void (0),
    isReactNative: this.isReactNative
  });

  return transport;
};

function clone (obj) {
  var o = {};
  for (var i in obj) {
    if (obj.hasOwnProperty(i)) {
      o[i] = obj[i];
    }
  }
  return o;
}

/**
 * Initializes transport to use and starts probe.
 *
 * @api private
 */
Socket.prototype.open = function () {
  var transport;
  if (this.rememberUpgrade && Socket.priorWebsocketSuccess && this.transports.indexOf('websocket') !== -1) {
    transport = 'websocket';
  } else if (0 === this.transports.length) {
    // Emit error on next tick so it can be listened to
    var self = this;
    setTimeout(function () {
      self.emit('error', 'No transports available');
    }, 0);
    return;
  } else {
    transport = this.transports[0];
  }
  this.readyState = 'opening';

  // Retry with the next transport if the transport is disabled (jsonp: false)
  try {
    transport = this.createTransport(transport);
  } catch (e) {
    this.transports.shift();
    this.open();
    return;
  }

  transport.open();
  this.setTransport(transport);
};

/**
 * Sets the current transport. Disables the existing one (if any).
 *
 * @api private
 */

Socket.prototype.setTransport = function (transport) {
  debug('setting transport %s', transport.name);
  var self = this;

  if (this.transport) {
    debug('clearing existing transport %s', this.transport.name);
    this.transport.removeAllListeners();
  }

  // set up transport
  this.transport = transport;

  // set up transport listeners
  transport
  .on('drain', function () {
    self.onDrain();
  })
  .on('packet', function (packet) {
    self.onPacket(packet);
  })
  .on('error', function (e) {
    self.onError(e);
  })
  .on('close', function () {
    self.onClose('transport close');
  });
};

/**
 * Probes a transport.
 *
 * @param {String} transport name
 * @api private
 */

Socket.prototype.probe = function (name) {
  debug('probing transport "%s"', name);
  var transport = this.createTransport(name, { probe: 1 });
  var failed = false;
  var self = this;

  Socket.priorWebsocketSuccess = false;

  function onTransportOpen () {
    if (self.onlyBinaryUpgrades) {
      var upgradeLosesBinary = !this.supportsBinary && self.transport.supportsBinary;
      failed = failed || upgradeLosesBinary;
    }
    if (failed) return;

    debug('probe transport "%s" opened', name);
    transport.send([{ type: 'ping', data: 'probe' }]);
    transport.once('packet', function (msg) {
      if (failed) return;
      if ('pong' === msg.type && 'probe' === msg.data) {
        debug('probe transport "%s" pong', name);
        self.upgrading = true;
        self.emit('upgrading', transport);
        if (!transport) return;
        Socket.priorWebsocketSuccess = 'websocket' === transport.name;

        debug('pausing current transport "%s"', self.transport.name);
        self.transport.pause(function () {
          if (failed) return;
          if ('closed' === self.readyState) return;
          debug('changing transport and sending upgrade packet');

          cleanup();

          self.setTransport(transport);
          transport.send([{ type: 'upgrade' }]);
          self.emit('upgrade', transport);
          transport = null;
          self.upgrading = false;
          self.flush();
        });
      } else {
        debug('probe transport "%s" failed', name);
        var err = new Error('probe error');
        err.transport = transport.name;
        self.emit('upgradeError', err);
      }
    });
  }

  function freezeTransport () {
    if (failed) return;

    // Any callback called by transport should be ignored since now
    failed = true;

    cleanup();

    transport.close();
    transport = null;
  }

  // Handle any error that happens while probing
  function onerror (err) {
    var error = new Error('probe error: ' + err);
    error.transport = transport.name;

    freezeTransport();

    debug('probe transport "%s" failed because of error: %s', name, err);

    self.emit('upgradeError', error);
  }

  function onTransportClose () {
    onerror('transport closed');
  }

  // When the socket is closed while we're probing
  function onclose () {
    onerror('socket closed');
  }

  // When the socket is upgraded while we're probing
  function onupgrade (to) {
    if (transport && to.name !== transport.name) {
      debug('"%s" works - aborting "%s"', to.name, transport.name);
      freezeTransport();
    }
  }

  // Remove all listeners on the transport and on self
  function cleanup () {
    transport.removeListener('open', onTransportOpen);
    transport.removeListener('error', onerror);
    transport.removeListener('close', onTransportClose);
    self.removeListener('close', onclose);
    self.removeListener('upgrading', onupgrade);
  }

  transport.once('open', onTransportOpen);
  transport.once('error', onerror);
  transport.once('close', onTransportClose);

  this.once('close', onclose);
  this.once('upgrading', onupgrade);

  transport.open();
};

/**
 * Called when connection is deemed open.
 *
 * @api public
 */

Socket.prototype.onOpen = function () {
  debug('socket open');
  this.readyState = 'open';
  Socket.priorWebsocketSuccess = 'websocket' === this.transport.name;
  this.emit('open');
  this.flush();

  // we check for `readyState` in case an `open`
  // listener already closed the socket
  if ('open' === this.readyState && this.upgrade && this.transport.pause) {
    debug('starting upgrade probes');
    for (var i = 0, l = this.upgrades.length; i < l; i++) {
      this.probe(this.upgrades[i]);
    }
  }
};

/**
 * Handles a packet.
 *
 * @api private
 */

Socket.prototype.onPacket = function (packet) {
  if ('opening' === this.readyState || 'open' === this.readyState ||
      'closing' === this.readyState) {
    debug('socket receive: type "%s", data "%s"', packet.type, packet.data);

    this.emit('packet', packet);

    // Socket is live - any packet counts
    this.emit('heartbeat');

    switch (packet.type) {
      case 'open':
        this.onHandshake(JSON.parse(packet.data));
        break;

      case 'pong':
        this.setPing();
        this.emit('pong');
        break;

      case 'error':
        var err = new Error('server error');
        err.code = packet.data;
        this.onError(err);
        break;

      case 'message':
        this.emit('data', packet.data);
        this.emit('message', packet.data);
        break;
    }
  } else {
    debug('packet received with socket readyState "%s"', this.readyState);
  }
};

/**
 * Called upon handshake completion.
 *
 * @param {Object} handshake obj
 * @api private
 */

Socket.prototype.onHandshake = function (data) {
  this.emit('handshake', data);
  this.id = data.sid;
  this.transport.query.sid = data.sid;
  this.upgrades = this.filterUpgrades(data.upgrades);
  this.pingInterval = data.pingInterval;
  this.pingTimeout = data.pingTimeout;
  this.onOpen();
  // In case open handler closes socket
  if ('closed' === this.readyState) return;
  this.setPing();

  // Prolong liveness of socket on heartbeat
  this.removeListener('heartbeat', this.onHeartbeat);
  this.on('heartbeat', this.onHeartbeat);
};

/**
 * Resets ping timeout.
 *
 * @api private
 */

Socket.prototype.onHeartbeat = function (timeout) {
  clearTimeout(this.pingTimeoutTimer);
  var self = this;
  self.pingTimeoutTimer = setTimeout(function () {
    if ('closed' === self.readyState) return;
    self.onClose('ping timeout');
  }, timeout || (self.pingInterval + self.pingTimeout));
};

/**
 * Pings server every `this.pingInterval` and expects response
 * within `this.pingTimeout` or closes connection.
 *
 * @api private
 */

Socket.prototype.setPing = function () {
  var self = this;
  clearTimeout(self.pingIntervalTimer);
  self.pingIntervalTimer = setTimeout(function () {
    debug('writing ping packet - expecting pong within %sms', self.pingTimeout);
    self.ping();
    self.onHeartbeat(self.pingTimeout);
  }, self.pingInterval);
};

/**
* Sends a ping packet.
*
* @api private
*/

Socket.prototype.ping = function () {
  var self = this;
  this.sendPacket('ping', function () {
    self.emit('ping');
  });
};

/**
 * Called on `drain` event
 *
 * @api private
 */

Socket.prototype.onDrain = function () {
  this.writeBuffer.splice(0, this.prevBufferLen);

  // setting prevBufferLen = 0 is very important
  // for example, when upgrading, upgrade packet is sent over,
  // and a nonzero prevBufferLen could cause problems on `drain`
  this.prevBufferLen = 0;

  if (0 === this.writeBuffer.length) {
    this.emit('drain');
  } else {
    this.flush();
  }
};

/**
 * Flush write buffers.
 *
 * @api private
 */

Socket.prototype.flush = function () {
  if ('closed' !== this.readyState && this.transport.writable &&
    !this.upgrading && this.writeBuffer.length) {
    debug('flushing %d packets in socket', this.writeBuffer.length);
    this.transport.send(this.writeBuffer);
    // keep track of current length of writeBuffer
    // splice writeBuffer and callbackBuffer on `drain`
    this.prevBufferLen = this.writeBuffer.length;
    this.emit('flush');
  }
};

/**
 * Sends a message.
 *
 * @param {String} message.
 * @param {Function} callback function.
 * @param {Object} options.
 * @return {Socket} for chaining.
 * @api public
 */

Socket.prototype.write =
Socket.prototype.send = function (msg, options, fn) {
  this.sendPacket('message', msg, options, fn);
  return this;
};

/**
 * Sends a packet.
 *
 * @param {String} packet type.
 * @param {String} data.
 * @param {Object} options.
 * @param {Function} callback function.
 * @api private
 */

Socket.prototype.sendPacket = function (type, data, options, fn) {
  if ('function' === typeof data) {
    fn = data;
    data = undefined;
  }

  if ('function' === typeof options) {
    fn = options;
    options = null;
  }

  if ('closing' === this.readyState || 'closed' === this.readyState) {
    return;
  }

  options = options || {};
  options.compress = false !== options.compress;

  var packet = {
    type: type,
    data: data,
    options: options
  };
  this.emit('packetCreate', packet);
  this.writeBuffer.push(packet);
  if (fn) this.once('flush', fn);
  this.flush();
};

/**
 * Closes the connection.
 *
 * @api private
 */

Socket.prototype.close = function () {
  if ('opening' === this.readyState || 'open' === this.readyState) {
    this.readyState = 'closing';

    var self = this;

    if (this.writeBuffer.length) {
      this.once('drain', function () {
        if (this.upgrading) {
          waitForUpgrade();
        } else {
          close();
        }
      });
    } else if (this.upgrading) {
      waitForUpgrade();
    } else {
      close();
    }
  }

  function close () {
    self.onClose('forced close');
    debug('socket closing - telling transport to close');
    self.transport.close();
  }

  function cleanupAndClose () {
    self.removeListener('upgrade', cleanupAndClose);
    self.removeListener('upgradeError', cleanupAndClose);
    close();
  }

  function waitForUpgrade () {
    // wait for upgrade to finish since we can't send packets while pausing a transport
    self.once('upgrade', cleanupAndClose);
    self.once('upgradeError', cleanupAndClose);
  }

  return this;
};

/**
 * Called upon transport error
 *
 * @api private
 */

Socket.prototype.onError = function (err) {
  debug('socket error %j', err);
  Socket.priorWebsocketSuccess = false;
  this.emit('error', err);
  this.onClose('transport error', err);
};

/**
 * Called upon transport close.
 *
 * @api private
 */

Socket.prototype.onClose = function (reason, desc) {
  if ('opening' === this.readyState || 'open' === this.readyState || 'closing' === this.readyState) {
    debug('socket close with reason: "%s"', reason);
    var self = this;

    // clear timers
    clearTimeout(this.pingIntervalTimer);
    clearTimeout(this.pingTimeoutTimer);

    // stop event from firing again for transport
    this.transport.removeAllListeners('close');

    // ensure transport won't stay open
    this.transport.close();

    // ignore further transport communication
    this.transport.removeAllListeners();

    // set ready state
    this.readyState = 'closed';

    // clear session id
    this.id = null;

    // emit close event
    this.emit('close', reason, desc);

    // clean buffers after, so users can still
    // grab the buffers on `close` event
    self.writeBuffer = [];
    self.prevBufferLen = 0;
  }
};

/**
 * Filters upgrades, returning only those matching client transports.
 *
 * @param {Array} server upgrades
 * @api private
 *
 */

Socket.prototype.filterUpgrades = function (upgrades) {
  var filteredUpgrades = [];
  for (var i = 0, j = upgrades.length; i < j; i++) {
    if (~index(this.transports, upgrades[i])) filteredUpgrades.push(upgrades[i]);
  }
  return filteredUpgrades;
};

},{"./transport":16,"./transports/index":17,"component-emitter":23,"debug":24,"engine.io-parser":27,"indexof":35,"parseqs":38,"parseuri":39}],16:[function(require,module,exports){
/**
 * Module dependencies.
 */

var parser = require('engine.io-parser');
var Emitter = require('component-emitter');

/**
 * Module exports.
 */

module.exports = Transport;

/**
 * Transport abstract constructor.
 *
 * @param {Object} options.
 * @api private
 */

function Transport (opts) {
  this.path = opts.path;
  this.hostname = opts.hostname;
  this.port = opts.port;
  this.secure = opts.secure;
  this.query = opts.query;
  this.timestampParam = opts.timestampParam;
  this.timestampRequests = opts.timestampRequests;
  this.readyState = '';
  this.agent = opts.agent || false;
  this.socket = opts.socket;
  this.enablesXDR = opts.enablesXDR;
  this.withCredentials = opts.withCredentials;

  // SSL options for Node.js client
  this.pfx = opts.pfx;
  this.key = opts.key;
  this.passphrase = opts.passphrase;
  this.cert = opts.cert;
  this.ca = opts.ca;
  this.ciphers = opts.ciphers;
  this.rejectUnauthorized = opts.rejectUnauthorized;
  this.forceNode = opts.forceNode;

  // results of ReactNative environment detection
  this.isReactNative = opts.isReactNative;

  // other options for Node.js client
  this.extraHeaders = opts.extraHeaders;
  this.localAddress = opts.localAddress;
}

/**
 * Mix in `Emitter`.
 */

Emitter(Transport.prototype);

/**
 * Emits an error.
 *
 * @param {String} str
 * @return {Transport} for chaining
 * @api public
 */

Transport.prototype.onError = function (msg, desc) {
  var err = new Error(msg);
  err.type = 'TransportError';
  err.description = desc;
  this.emit('error', err);
  return this;
};

/**
 * Opens the transport.
 *
 * @api public
 */

Transport.prototype.open = function () {
  if ('closed' === this.readyState || '' === this.readyState) {
    this.readyState = 'opening';
    this.doOpen();
  }

  return this;
};

/**
 * Closes the transport.
 *
 * @api private
 */

Transport.prototype.close = function () {
  if ('opening' === this.readyState || 'open' === this.readyState) {
    this.doClose();
    this.onClose();
  }

  return this;
};

/**
 * Sends multiple packets.
 *
 * @param {Array} packets
 * @api private
 */

Transport.prototype.send = function (packets) {
  if ('open' === this.readyState) {
    this.write(packets);
  } else {
    throw new Error('Transport not open');
  }
};

/**
 * Called upon open
 *
 * @api private
 */

Transport.prototype.onOpen = function () {
  this.readyState = 'open';
  this.writable = true;
  this.emit('open');
};

/**
 * Called with data.
 *
 * @param {String} data
 * @api private
 */

Transport.prototype.onData = function (data) {
  var packet = parser.decodePacket(data, this.socket.binaryType);
  this.onPacket(packet);
};

/**
 * Called with a decoded packet.
 */

Transport.prototype.onPacket = function (packet) {
  this.emit('packet', packet);
};

/**
 * Called upon close.
 *
 * @api private
 */

Transport.prototype.onClose = function () {
  this.readyState = 'closed';
  this.emit('close');
};

},{"component-emitter":23,"engine.io-parser":27}],17:[function(require,module,exports){
/**
 * Module dependencies
 */

var XMLHttpRequest = require('xmlhttprequest-ssl');
var XHR = require('./polling-xhr');
var JSONP = require('./polling-jsonp');
var websocket = require('./websocket');

/**
 * Export transports.
 */

exports.polling = polling;
exports.websocket = websocket;

/**
 * Polling transport polymorphic constructor.
 * Decides on xhr vs jsonp based on feature detection.
 *
 * @api private
 */

function polling (opts) {
  var xhr;
  var xd = false;
  var xs = false;
  var jsonp = false !== opts.jsonp;

  if (typeof location !== 'undefined') {
    var isSSL = 'https:' === location.protocol;
    var port = location.port;

    // some user agents have empty `location.port`
    if (!port) {
      port = isSSL ? 443 : 80;
    }

    xd = opts.hostname !== location.hostname || port !== opts.port;
    xs = opts.secure !== isSSL;
  }

  opts.xdomain = xd;
  opts.xscheme = xs;
  xhr = new XMLHttpRequest(opts);

  if ('open' in xhr && !opts.forceJSONP) {
    return new XHR(opts);
  } else {
    if (!jsonp) throw new Error('JSONP disabled');
    return new JSONP(opts);
  }
}

},{"./polling-jsonp":18,"./polling-xhr":19,"./websocket":21,"xmlhttprequest-ssl":22}],18:[function(require,module,exports){
/**
 * Module requirements.
 */

var Polling = require('./polling');
var inherit = require('component-inherit');
var globalThis = require('../globalThis');

/**
 * Module exports.
 */

module.exports = JSONPPolling;

/**
 * Cached regular expressions.
 */

var rNewline = /\n/g;
var rEscapedNewline = /\\n/g;

/**
 * Global JSONP callbacks.
 */

var callbacks;

/**
 * Noop.
 */

function empty () { }

/**
 * JSONP Polling constructor.
 *
 * @param {Object} opts.
 * @api public
 */

function JSONPPolling (opts) {
  Polling.call(this, opts);

  this.query = this.query || {};

  // define global callbacks array if not present
  // we do this here (lazily) to avoid unneeded global pollution
  if (!callbacks) {
    // we need to consider multiple engines in the same page
    callbacks = globalThis.___eio = (globalThis.___eio || []);
  }

  // callback identifier
  this.index = callbacks.length;

  // add callback to jsonp global
  var self = this;
  callbacks.push(function (msg) {
    self.onData(msg);
  });

  // append to query string
  this.query.j = this.index;

  // prevent spurious errors from being emitted when the window is unloaded
  if (typeof addEventListener === 'function') {
    addEventListener('beforeunload', function () {
      if (self.script) self.script.onerror = empty;
    }, false);
  }
}

/**
 * Inherits from Polling.
 */

inherit(JSONPPolling, Polling);

/*
 * JSONP only supports binary as base64 encoded strings
 */

JSONPPolling.prototype.supportsBinary = false;

/**
 * Closes the socket.
 *
 * @api private
 */

JSONPPolling.prototype.doClose = function () {
  if (this.script) {
    this.script.parentNode.removeChild(this.script);
    this.script = null;
  }

  if (this.form) {
    this.form.parentNode.removeChild(this.form);
    this.form = null;
    this.iframe = null;
  }

  Polling.prototype.doClose.call(this);
};

/**
 * Starts a poll cycle.
 *
 * @api private
 */

JSONPPolling.prototype.doPoll = function () {
  var self = this;
  var script = document.createElement('script');

  if (this.script) {
    this.script.parentNode.removeChild(this.script);
    this.script = null;
  }

  script.async = true;
  script.src = this.uri();
  script.onerror = function (e) {
    self.onError('jsonp poll error', e);
  };

  var insertAt = document.getElementsByTagName('script')[0];
  if (insertAt) {
    insertAt.parentNode.insertBefore(script, insertAt);
  } else {
    (document.head || document.body).appendChild(script);
  }
  this.script = script;

  var isUAgecko = 'undefined' !== typeof navigator && /gecko/i.test(navigator.userAgent);

  if (isUAgecko) {
    setTimeout(function () {
      var iframe = document.createElement('iframe');
      document.body.appendChild(iframe);
      document.body.removeChild(iframe);
    }, 100);
  }
};

/**
 * Writes with a hidden iframe.
 *
 * @param {String} data to send
 * @param {Function} called upon flush.
 * @api private
 */

JSONPPolling.prototype.doWrite = function (data, fn) {
  var self = this;

  if (!this.form) {
    var form = document.createElement('form');
    var area = document.createElement('textarea');
    var id = this.iframeId = 'eio_iframe_' + this.index;
    var iframe;

    form.className = 'socketio';
    form.style.position = 'absolute';
    form.style.top = '-1000px';
    form.style.left = '-1000px';
    form.target = id;
    form.method = 'POST';
    form.setAttribute('accept-charset', 'utf-8');
    area.name = 'd';
    form.appendChild(area);
    document.body.appendChild(form);

    this.form = form;
    this.area = area;
  }

  this.form.action = this.uri();

  function complete () {
    initIframe();
    fn();
  }

  function initIframe () {
    if (self.iframe) {
      try {
        self.form.removeChild(self.iframe);
      } catch (e) {
        self.onError('jsonp polling iframe removal error', e);
      }
    }

    try {
      // ie6 dynamic iframes with target="" support (thanks Chris Lambacher)
      var html = '<iframe src="javascript:0" name="' + self.iframeId + '">';
      iframe = document.createElement(html);
    } catch (e) {
      iframe = document.createElement('iframe');
      iframe.name = self.iframeId;
      iframe.src = 'javascript:0';
    }

    iframe.id = self.iframeId;

    self.form.appendChild(iframe);
    self.iframe = iframe;
  }

  initIframe();

  // escape \n to prevent it from being converted into \r\n by some UAs
  // double escaping is required for escaped new lines because unescaping of new lines can be done safely on server-side
  data = data.replace(rEscapedNewline, '\\\n');
  this.area.value = data.replace(rNewline, '\\n');

  try {
    this.form.submit();
  } catch (e) {}

  if (this.iframe.attachEvent) {
    this.iframe.onreadystatechange = function () {
      if (self.iframe.readyState === 'complete') {
        complete();
      }
    };
  } else {
    this.iframe.onload = complete;
  }
};

},{"../globalThis":13,"./polling":20,"component-inherit":12}],19:[function(require,module,exports){
/* global attachEvent */

/**
 * Module requirements.
 */

var XMLHttpRequest = require('xmlhttprequest-ssl');
var Polling = require('./polling');
var Emitter = require('component-emitter');
var inherit = require('component-inherit');
var debug = require('debug')('engine.io-client:polling-xhr');
var globalThis = require('../globalThis');

/**
 * Module exports.
 */

module.exports = XHR;
module.exports.Request = Request;

/**
 * Empty function
 */

function empty () {}

/**
 * XHR Polling constructor.
 *
 * @param {Object} opts
 * @api public
 */

function XHR (opts) {
  Polling.call(this, opts);
  this.requestTimeout = opts.requestTimeout;
  this.extraHeaders = opts.extraHeaders;

  if (typeof location !== 'undefined') {
    var isSSL = 'https:' === location.protocol;
    var port = location.port;

    // some user agents have empty `location.port`
    if (!port) {
      port = isSSL ? 443 : 80;
    }

    this.xd = (typeof location !== 'undefined' && opts.hostname !== location.hostname) ||
      port !== opts.port;
    this.xs = opts.secure !== isSSL;
  }
}

/**
 * Inherits from Polling.
 */

inherit(XHR, Polling);

/**
 * XHR supports binary
 */

XHR.prototype.supportsBinary = true;

/**
 * Creates a request.
 *
 * @param {String} method
 * @api private
 */

XHR.prototype.request = function (opts) {
  opts = opts || {};
  opts.uri = this.uri();
  opts.xd = this.xd;
  opts.xs = this.xs;
  opts.agent = this.agent || false;
  opts.supportsBinary = this.supportsBinary;
  opts.enablesXDR = this.enablesXDR;
  opts.withCredentials = this.withCredentials;

  // SSL options for Node.js client
  opts.pfx = this.pfx;
  opts.key = this.key;
  opts.passphrase = this.passphrase;
  opts.cert = this.cert;
  opts.ca = this.ca;
  opts.ciphers = this.ciphers;
  opts.rejectUnauthorized = this.rejectUnauthorized;
  opts.requestTimeout = this.requestTimeout;

  // other options for Node.js client
  opts.extraHeaders = this.extraHeaders;

  return new Request(opts);
};

/**
 * Sends data.
 *
 * @param {String} data to send.
 * @param {Function} called upon flush.
 * @api private
 */

XHR.prototype.doWrite = function (data, fn) {
  var isBinary = typeof data !== 'string' && data !== undefined;
  var req = this.request({ method: 'POST', data: data, isBinary: isBinary });
  var self = this;
  req.on('success', fn);
  req.on('error', function (err) {
    self.onError('xhr post error', err);
  });
  this.sendXhr = req;
};

/**
 * Starts a poll cycle.
 *
 * @api private
 */

XHR.prototype.doPoll = function () {
  debug('xhr poll');
  var req = this.request();
  var self = this;
  req.on('data', function (data) {
    self.onData(data);
  });
  req.on('error', function (err) {
    self.onError('xhr poll error', err);
  });
  this.pollXhr = req;
};

/**
 * Request constructor
 *
 * @param {Object} options
 * @api public
 */

function Request (opts) {
  this.method = opts.method || 'GET';
  this.uri = opts.uri;
  this.xd = !!opts.xd;
  this.xs = !!opts.xs;
  this.async = false !== opts.async;
  this.data = undefined !== opts.data ? opts.data : null;
  this.agent = opts.agent;
  this.isBinary = opts.isBinary;
  this.supportsBinary = opts.supportsBinary;
  this.enablesXDR = opts.enablesXDR;
  this.withCredentials = opts.withCredentials;
  this.requestTimeout = opts.requestTimeout;

  // SSL options for Node.js client
  this.pfx = opts.pfx;
  this.key = opts.key;
  this.passphrase = opts.passphrase;
  this.cert = opts.cert;
  this.ca = opts.ca;
  this.ciphers = opts.ciphers;
  this.rejectUnauthorized = opts.rejectUnauthorized;

  // other options for Node.js client
  this.extraHeaders = opts.extraHeaders;

  this.create();
}

/**
 * Mix in `Emitter`.
 */

Emitter(Request.prototype);

/**
 * Creates the XHR object and sends the request.
 *
 * @api private
 */

Request.prototype.create = function () {
  var opts = { agent: this.agent, xdomain: this.xd, xscheme: this.xs, enablesXDR: this.enablesXDR };

  // SSL options for Node.js client
  opts.pfx = this.pfx;
  opts.key = this.key;
  opts.passphrase = this.passphrase;
  opts.cert = this.cert;
  opts.ca = this.ca;
  opts.ciphers = this.ciphers;
  opts.rejectUnauthorized = this.rejectUnauthorized;

  var xhr = this.xhr = new XMLHttpRequest(opts);
  var self = this;

  try {
    debug('xhr open %s: %s', this.method, this.uri);
    xhr.open(this.method, this.uri, this.async);
    try {
      if (this.extraHeaders) {
        xhr.setDisableHeaderCheck && xhr.setDisableHeaderCheck(true);
        for (var i in this.extraHeaders) {
          if (this.extraHeaders.hasOwnProperty(i)) {
            xhr.setRequestHeader(i, this.extraHeaders[i]);
          }
        }
      }
    } catch (e) {}

    if ('POST' === this.method) {
      try {
        if (this.isBinary) {
          xhr.setRequestHeader('Content-type', 'application/octet-stream');
        } else {
          xhr.setRequestHeader('Content-type', 'text/plain;charset=UTF-8');
        }
      } catch (e) {}
    }

    try {
      xhr.setRequestHeader('Accept', '*/*');
    } catch (e) {}

    // ie6 check
    if ('withCredentials' in xhr) {
      xhr.withCredentials = this.withCredentials;
    }

    if (this.requestTimeout) {
      xhr.timeout = this.requestTimeout;
    }

    if (this.hasXDR()) {
      xhr.onload = function () {
        self.onLoad();
      };
      xhr.onerror = function () {
        self.onError(xhr.responseText);
      };
    } else {
      xhr.onreadystatechange = function () {
        if (xhr.readyState === 2) {
          try {
            var contentType = xhr.getResponseHeader('Content-Type');
            if (self.supportsBinary && contentType === 'application/octet-stream' || contentType === 'application/octet-stream; charset=UTF-8') {
              xhr.responseType = 'arraybuffer';
            }
          } catch (e) {}
        }
        if (4 !== xhr.readyState) return;
        if (200 === xhr.status || 1223 === xhr.status) {
          self.onLoad();
        } else {
          // make sure the `error` event handler that's user-set
          // does not throw in the same tick and gets caught here
          setTimeout(function () {
            self.onError(typeof xhr.status === 'number' ? xhr.status : 0);
          }, 0);
        }
      };
    }

    debug('xhr data %s', this.data);
    xhr.send(this.data);
  } catch (e) {
    // Need to defer since .create() is called directly fhrom the constructor
    // and thus the 'error' event can only be only bound *after* this exception
    // occurs.  Therefore, also, we cannot throw here at all.
    setTimeout(function () {
      self.onError(e);
    }, 0);
    return;
  }

  if (typeof document !== 'undefined') {
    this.index = Request.requestsCount++;
    Request.requests[this.index] = this;
  }
};

/**
 * Called upon successful response.
 *
 * @api private
 */

Request.prototype.onSuccess = function () {
  this.emit('success');
  this.cleanup();
};

/**
 * Called if we have data.
 *
 * @api private
 */

Request.prototype.onData = function (data) {
  this.emit('data', data);
  this.onSuccess();
};

/**
 * Called upon error.
 *
 * @api private
 */

Request.prototype.onError = function (err) {
  this.emit('error', err);
  this.cleanup(true);
};

/**
 * Cleans up house.
 *
 * @api private
 */

Request.prototype.cleanup = function (fromError) {
  if ('undefined' === typeof this.xhr || null === this.xhr) {
    return;
  }
  // xmlhttprequest
  if (this.hasXDR()) {
    this.xhr.onload = this.xhr.onerror = empty;
  } else {
    this.xhr.onreadystatechange = empty;
  }

  if (fromError) {
    try {
      this.xhr.abort();
    } catch (e) {}
  }

  if (typeof document !== 'undefined') {
    delete Request.requests[this.index];
  }

  this.xhr = null;
};

/**
 * Called upon load.
 *
 * @api private
 */

Request.prototype.onLoad = function () {
  var data;
  try {
    var contentType;
    try {
      contentType = this.xhr.getResponseHeader('Content-Type');
    } catch (e) {}
    if (contentType === 'application/octet-stream' || contentType === 'application/octet-stream; charset=UTF-8') {
      data = this.xhr.response || this.xhr.responseText;
    } else {
      data = this.xhr.responseText;
    }
  } catch (e) {
    this.onError(e);
  }
  if (null != data) {
    this.onData(data);
  }
};

/**
 * Check if it has XDomainRequest.
 *
 * @api private
 */

Request.prototype.hasXDR = function () {
  return typeof XDomainRequest !== 'undefined' && !this.xs && this.enablesXDR;
};

/**
 * Aborts the request.
 *
 * @api public
 */

Request.prototype.abort = function () {
  this.cleanup();
};

/**
 * Aborts pending requests when unloading the window. This is needed to prevent
 * memory leaks (e.g. when using IE) and to ensure that no spurious error is
 * emitted.
 */

Request.requestsCount = 0;
Request.requests = {};

if (typeof document !== 'undefined') {
  if (typeof attachEvent === 'function') {
    attachEvent('onunload', unloadHandler);
  } else if (typeof addEventListener === 'function') {
    var terminationEvent = 'onpagehide' in globalThis ? 'pagehide' : 'unload';
    addEventListener(terminationEvent, unloadHandler, false);
  }
}

function unloadHandler () {
  for (var i in Request.requests) {
    if (Request.requests.hasOwnProperty(i)) {
      Request.requests[i].abort();
    }
  }
}

},{"../globalThis":13,"./polling":20,"component-emitter":23,"component-inherit":12,"debug":24,"xmlhttprequest-ssl":22}],20:[function(require,module,exports){
/**
 * Module dependencies.
 */

var Transport = require('../transport');
var parseqs = require('parseqs');
var parser = require('engine.io-parser');
var inherit = require('component-inherit');
var yeast = require('yeast');
var debug = require('debug')('engine.io-client:polling');

/**
 * Module exports.
 */

module.exports = Polling;

/**
 * Is XHR2 supported?
 */

var hasXHR2 = (function () {
  var XMLHttpRequest = require('xmlhttprequest-ssl');
  var xhr = new XMLHttpRequest({ xdomain: false });
  return null != xhr.responseType;
})();

/**
 * Polling interface.
 *
 * @param {Object} opts
 * @api private
 */

function Polling (opts) {
  var forceBase64 = (opts && opts.forceBase64);
  if (!hasXHR2 || forceBase64) {
    this.supportsBinary = false;
  }
  Transport.call(this, opts);
}

/**
 * Inherits from Transport.
 */

inherit(Polling, Transport);

/**
 * Transport name.
 */

Polling.prototype.name = 'polling';

/**
 * Opens the socket (triggers polling). We write a PING message to determine
 * when the transport is open.
 *
 * @api private
 */

Polling.prototype.doOpen = function () {
  this.poll();
};

/**
 * Pauses polling.
 *
 * @param {Function} callback upon buffers are flushed and transport is paused
 * @api private
 */

Polling.prototype.pause = function (onPause) {
  var self = this;

  this.readyState = 'pausing';

  function pause () {
    debug('paused');
    self.readyState = 'paused';
    onPause();
  }

  if (this.polling || !this.writable) {
    var total = 0;

    if (this.polling) {
      debug('we are currently polling - waiting to pause');
      total++;
      this.once('pollComplete', function () {
        debug('pre-pause polling complete');
        --total || pause();
      });
    }

    if (!this.writable) {
      debug('we are currently writing - waiting to pause');
      total++;
      this.once('drain', function () {
        debug('pre-pause writing complete');
        --total || pause();
      });
    }
  } else {
    pause();
  }
};

/**
 * Starts polling cycle.
 *
 * @api public
 */

Polling.prototype.poll = function () {
  debug('polling');
  this.polling = true;
  this.doPoll();
  this.emit('poll');
};

/**
 * Overloads onData to detect payloads.
 *
 * @api private
 */

Polling.prototype.onData = function (data) {
  var self = this;
  debug('polling got data %s', data);
  var callback = function (packet, index, total) {
    // if its the first message we consider the transport open
    if ('opening' === self.readyState) {
      self.onOpen();
    }

    // if its a close packet, we close the ongoing requests
    if ('close' === packet.type) {
      self.onClose();
      return false;
    }

    // otherwise bypass onData and handle the message
    self.onPacket(packet);
  };

  // decode payload
  parser.decodePayload(data, this.socket.binaryType, callback);

  // if an event did not trigger closing
  if ('closed' !== this.readyState) {
    // if we got data we're not polling
    this.polling = false;
    this.emit('pollComplete');

    if ('open' === this.readyState) {
      this.poll();
    } else {
      debug('ignoring poll - transport state "%s"', this.readyState);
    }
  }
};

/**
 * For polling, send a close packet.
 *
 * @api private
 */

Polling.prototype.doClose = function () {
  var self = this;

  function close () {
    debug('writing close packet');
    self.write([{ type: 'close' }]);
  }

  if ('open' === this.readyState) {
    debug('transport open - closing');
    close();
  } else {
    // in case we're trying to close while
    // handshaking is in progress (GH-164)
    debug('transport not open - deferring close');
    this.once('open', close);
  }
};

/**
 * Writes a packets payload.
 *
 * @param {Array} data packets
 * @param {Function} drain callback
 * @api private
 */

Polling.prototype.write = function (packets) {
  var self = this;
  this.writable = false;
  var callbackfn = function () {
    self.writable = true;
    self.emit('drain');
  };

  parser.encodePayload(packets, this.supportsBinary, function (data) {
    self.doWrite(data, callbackfn);
  });
};

/**
 * Generates uri for connection.
 *
 * @api private
 */

Polling.prototype.uri = function () {
  var query = this.query || {};
  var schema = this.secure ? 'https' : 'http';
  var port = '';

  // cache busting is forced
  if (false !== this.timestampRequests) {
    query[this.timestampParam] = yeast();
  }

  if (!this.supportsBinary && !query.sid) {
    query.b64 = 1;
  }

  query = parseqs.encode(query);

  // avoid port if default for schema
  if (this.port && (('https' === schema && Number(this.port) !== 443) ||
     ('http' === schema && Number(this.port) !== 80))) {
    port = ':' + this.port;
  }

  // prepend ? to query
  if (query.length) {
    query = '?' + query;
  }

  var ipv6 = this.hostname.indexOf(':') !== -1;
  return schema + '://' + (ipv6 ? '[' + this.hostname + ']' : this.hostname) + port + this.path + query;
};

},{"../transport":16,"component-inherit":12,"debug":24,"engine.io-parser":27,"parseqs":38,"xmlhttprequest-ssl":22,"yeast":81}],21:[function(require,module,exports){
(function (Buffer){(function (){
/**
 * Module dependencies.
 */

var Transport = require('../transport');
var parser = require('engine.io-parser');
var parseqs = require('parseqs');
var inherit = require('component-inherit');
var yeast = require('yeast');
var debug = require('debug')('engine.io-client:websocket');

var BrowserWebSocket, NodeWebSocket;

if (typeof WebSocket !== 'undefined') {
  BrowserWebSocket = WebSocket;
} else if (typeof self !== 'undefined') {
  BrowserWebSocket = self.WebSocket || self.MozWebSocket;
}

if (typeof window === 'undefined') {
  try {
    NodeWebSocket = require('ws');
  } catch (e) { }
}

/**
 * Get either the `WebSocket` or `MozWebSocket` globals
 * in the browser or try to resolve WebSocket-compatible
 * interface exposed by `ws` for Node-like environment.
 */

var WebSocketImpl = BrowserWebSocket || NodeWebSocket;

/**
 * Module exports.
 */

module.exports = WS;

/**
 * WebSocket transport constructor.
 *
 * @api {Object} connection options
 * @api public
 */

function WS (opts) {
  var forceBase64 = (opts && opts.forceBase64);
  if (forceBase64) {
    this.supportsBinary = false;
  }
  this.perMessageDeflate = opts.perMessageDeflate;
  this.usingBrowserWebSocket = BrowserWebSocket && !opts.forceNode;
  this.protocols = opts.protocols;
  if (!this.usingBrowserWebSocket) {
    WebSocketImpl = NodeWebSocket;
  }
  Transport.call(this, opts);
}

/**
 * Inherits from Transport.
 */

inherit(WS, Transport);

/**
 * Transport name.
 *
 * @api public
 */

WS.prototype.name = 'websocket';

/*
 * WebSockets support binary
 */

WS.prototype.supportsBinary = true;

/**
 * Opens socket.
 *
 * @api private
 */

WS.prototype.doOpen = function () {
  if (!this.check()) {
    // let probe timeout
    return;
  }

  var uri = this.uri();
  var protocols = this.protocols;

  var opts = {};

  if (!this.isReactNative) {
    opts.agent = this.agent;
    opts.perMessageDeflate = this.perMessageDeflate;

    // SSL options for Node.js client
    opts.pfx = this.pfx;
    opts.key = this.key;
    opts.passphrase = this.passphrase;
    opts.cert = this.cert;
    opts.ca = this.ca;
    opts.ciphers = this.ciphers;
    opts.rejectUnauthorized = this.rejectUnauthorized;
  }

  if (this.extraHeaders) {
    opts.headers = this.extraHeaders;
  }
  if (this.localAddress) {
    opts.localAddress = this.localAddress;
  }

  try {
    this.ws =
      this.usingBrowserWebSocket && !this.isReactNative
        ? protocols
          ? new WebSocketImpl(uri, protocols)
          : new WebSocketImpl(uri)
        : new WebSocketImpl(uri, protocols, opts);
  } catch (err) {
    return this.emit('error', err);
  }

  if (this.ws.binaryType === undefined) {
    this.supportsBinary = false;
  }

  if (this.ws.supports && this.ws.supports.binary) {
    this.supportsBinary = true;
    this.ws.binaryType = 'nodebuffer';
  } else {
    this.ws.binaryType = 'arraybuffer';
  }

  this.addEventListeners();
};

/**
 * Adds event listeners to the socket
 *
 * @api private
 */

WS.prototype.addEventListeners = function () {
  var self = this;

  this.ws.onopen = function () {
    self.onOpen();
  };
  this.ws.onclose = function () {
    self.onClose();
  };
  this.ws.onmessage = function (ev) {
    self.onData(ev.data);
  };
  this.ws.onerror = function (e) {
    self.onError('websocket error', e);
  };
};

/**
 * Writes data to socket.
 *
 * @param {Array} array of packets.
 * @api private
 */

WS.prototype.write = function (packets) {
  var self = this;
  this.writable = false;

  // encodePacket efficient as it uses WS framing
  // no need for encodePayload
  var total = packets.length;
  for (var i = 0, l = total; i < l; i++) {
    (function (packet) {
      parser.encodePacket(packet, self.supportsBinary, function (data) {
        if (!self.usingBrowserWebSocket) {
          // always create a new object (GH-437)
          var opts = {};
          if (packet.options) {
            opts.compress = packet.options.compress;
          }

          if (self.perMessageDeflate) {
            var len = 'string' === typeof data ? Buffer.byteLength(data) : data.length;
            if (len < self.perMessageDeflate.threshold) {
              opts.compress = false;
            }
          }
        }

        // Sometimes the websocket has already been closed but the browser didn't
        // have a chance of informing us about it yet, in that case send will
        // throw an error
        try {
          if (self.usingBrowserWebSocket) {
            // TypeError is thrown when passing the second argument on Safari
            self.ws.send(data);
          } else {
            self.ws.send(data, opts);
          }
        } catch (e) {
          debug('websocket closed before onclose event');
        }

        --total || done();
      });
    })(packets[i]);
  }

  function done () {
    self.emit('flush');

    // fake drain
    // defer to next tick to allow Socket to clear writeBuffer
    setTimeout(function () {
      self.writable = true;
      self.emit('drain');
    }, 0);
  }
};

/**
 * Called upon close
 *
 * @api private
 */

WS.prototype.onClose = function () {
  Transport.prototype.onClose.call(this);
};

/**
 * Closes socket.
 *
 * @api private
 */

WS.prototype.doClose = function () {
  if (typeof this.ws !== 'undefined') {
    this.ws.close();
  }
};

/**
 * Generates uri for connection.
 *
 * @api private
 */

WS.prototype.uri = function () {
  var query = this.query || {};
  var schema = this.secure ? 'wss' : 'ws';
  var port = '';

  // avoid port if default for schema
  if (this.port && (('wss' === schema && Number(this.port) !== 443) ||
    ('ws' === schema && Number(this.port) !== 80))) {
    port = ':' + this.port;
  }

  // append timestamp to URI
  if (this.timestampRequests) {
    query[this.timestampParam] = yeast();
  }

  // communicate binary support capabilities
  if (!this.supportsBinary) {
    query.b64 = 1;
  }

  query = parseqs.encode(query);

  // prepend ? to query
  if (query.length) {
    query = '?' + query;
  }

  var ipv6 = this.hostname.indexOf(':') !== -1;
  return schema + '://' + (ipv6 ? '[' + this.hostname + ']' : this.hostname) + port + this.path + query;
};

/**
 * Feature detection for WebSocket.
 *
 * @return {Boolean} whether this transport is available.
 * @api public
 */

WS.prototype.check = function () {
  return !!WebSocketImpl && !('__initialize' in WebSocketImpl && this.name === WS.prototype.name);
};

}).call(this)}).call(this,require("buffer").Buffer)
},{"../transport":16,"buffer":9,"component-inherit":12,"debug":24,"engine.io-parser":27,"parseqs":38,"ws":8,"yeast":81}],22:[function(require,module,exports){
// browser shim for xmlhttprequest module

var hasCORS = require('has-cors');
var globalThis = require('./globalThis');

module.exports = function (opts) {
  var xdomain = opts.xdomain;

  // scheme must be same when usign XDomainRequest
  // http://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx
  var xscheme = opts.xscheme;

  // XDomainRequest has a flow of not sending cookie, therefore it should be disabled as a default.
  // https://github.com/Automattic/engine.io-client/pull/217
  var enablesXDR = opts.enablesXDR;

  // XMLHttpRequest can be disabled on IE
  try {
    if ('undefined' !== typeof XMLHttpRequest && (!xdomain || hasCORS)) {
      return new XMLHttpRequest();
    }
  } catch (e) { }

  // Use XDomainRequest for IE8 if enablesXDR is true
  // because loading bar keeps flashing when using jsonp-polling
  // https://github.com/yujiosaka/socke.io-ie8-loading-example
  try {
    if ('undefined' !== typeof XDomainRequest && !xscheme && enablesXDR) {
      return new XDomainRequest();
    }
  } catch (e) { }

  if (!xdomain) {
    try {
      return new globalThis[['Active'].concat('Object').join('X')]('Microsoft.XMLHTTP');
    } catch (e) { }
  }
};

},{"./globalThis":13,"has-cors":33}],23:[function(require,module,exports){

/**
 * Expose `Emitter`.
 */

if (typeof module !== 'undefined') {
  module.exports = Emitter;
}

/**
 * Initialize a new `Emitter`.
 *
 * @api public
 */

function Emitter(obj) {
  if (obj) return mixin(obj);
};

/**
 * Mixin the emitter properties.
 *
 * @param {Object} obj
 * @return {Object}
 * @api private
 */

function mixin(obj) {
  for (var key in Emitter.prototype) {
    obj[key] = Emitter.prototype[key];
  }
  return obj;
}

/**
 * Listen on the given `event` with `fn`.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.on =
Emitter.prototype.addEventListener = function(event, fn){
  this._callbacks = this._callbacks || {};
  (this._callbacks['$' + event] = this._callbacks['$' + event] || [])
    .push(fn);
  return this;
};

/**
 * Adds an `event` listener that will be invoked a single
 * time then automatically removed.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.once = function(event, fn){
  function on() {
    this.off(event, on);
    fn.apply(this, arguments);
  }

  on.fn = fn;
  this.on(event, on);
  return this;
};

/**
 * Remove the given callback for `event` or all
 * registered callbacks.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.off =
Emitter.prototype.removeListener =
Emitter.prototype.removeAllListeners =
Emitter.prototype.removeEventListener = function(event, fn){
  this._callbacks = this._callbacks || {};

  // all
  if (0 == arguments.length) {
    this._callbacks = {};
    return this;
  }

  // specific event
  var callbacks = this._callbacks['$' + event];
  if (!callbacks) return this;

  // remove all handlers
  if (1 == arguments.length) {
    delete this._callbacks['$' + event];
    return this;
  }

  // remove specific handler
  var cb;
  for (var i = 0; i < callbacks.length; i++) {
    cb = callbacks[i];
    if (cb === fn || cb.fn === fn) {
      callbacks.splice(i, 1);
      break;
    }
  }

  // Remove event specific arrays for event types that no
  // one is subscribed for to avoid memory leak.
  if (callbacks.length === 0) {
    delete this._callbacks['$' + event];
  }

  return this;
};

/**
 * Emit `event` with the given args.
 *
 * @param {String} event
 * @param {Mixed} ...
 * @return {Emitter}
 */

Emitter.prototype.emit = function(event){
  this._callbacks = this._callbacks || {};

  var args = new Array(arguments.length - 1)
    , callbacks = this._callbacks['$' + event];

  for (var i = 1; i < arguments.length; i++) {
    args[i - 1] = arguments[i];
  }

  if (callbacks) {
    callbacks = callbacks.slice(0);
    for (var i = 0, len = callbacks.length; i < len; ++i) {
      callbacks[i].apply(this, args);
    }
  }

  return this;
};

/**
 * Return array of callbacks for `event`.
 *
 * @param {String} event
 * @return {Array}
 * @api public
 */

Emitter.prototype.listeners = function(event){
  this._callbacks = this._callbacks || {};
  return this._callbacks['$' + event] || [];
};

/**
 * Check if this emitter has `event` handlers.
 *
 * @param {String} event
 * @return {Boolean}
 * @api public
 */

Emitter.prototype.hasListeners = function(event){
  return !! this.listeners(event).length;
};

},{}],24:[function(require,module,exports){
(function (process){(function (){
/* eslint-env browser */

/**
 * This is the web browser implementation of `debug()`.
 */

exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
exports.storage = localstorage();

/**
 * Colors.
 */

exports.colors = [
	'#0000CC',
	'#0000FF',
	'#0033CC',
	'#0033FF',
	'#0066CC',
	'#0066FF',
	'#0099CC',
	'#0099FF',
	'#00CC00',
	'#00CC33',
	'#00CC66',
	'#00CC99',
	'#00CCCC',
	'#00CCFF',
	'#3300CC',
	'#3300FF',
	'#3333CC',
	'#3333FF',
	'#3366CC',
	'#3366FF',
	'#3399CC',
	'#3399FF',
	'#33CC00',
	'#33CC33',
	'#33CC66',
	'#33CC99',
	'#33CCCC',
	'#33CCFF',
	'#6600CC',
	'#6600FF',
	'#6633CC',
	'#6633FF',
	'#66CC00',
	'#66CC33',
	'#9900CC',
	'#9900FF',
	'#9933CC',
	'#9933FF',
	'#99CC00',
	'#99CC33',
	'#CC0000',
	'#CC0033',
	'#CC0066',
	'#CC0099',
	'#CC00CC',
	'#CC00FF',
	'#CC3300',
	'#CC3333',
	'#CC3366',
	'#CC3399',
	'#CC33CC',
	'#CC33FF',
	'#CC6600',
	'#CC6633',
	'#CC9900',
	'#CC9933',
	'#CCCC00',
	'#CCCC33',
	'#FF0000',
	'#FF0033',
	'#FF0066',
	'#FF0099',
	'#FF00CC',
	'#FF00FF',
	'#FF3300',
	'#FF3333',
	'#FF3366',
	'#FF3399',
	'#FF33CC',
	'#FF33FF',
	'#FF6600',
	'#FF6633',
	'#FF9900',
	'#FF9933',
	'#FFCC00',
	'#FFCC33'
];

/**
 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 * and the Firebug extension (any Firefox version) are known
 * to support "%c" CSS customizations.
 *
 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 */

// eslint-disable-next-line complexity
function useColors() {
	// NB: In an Electron preload script, document will be defined but not fully
	// initialized. Since we know we're in Chrome, we'll just detect this case
	// explicitly
	if (typeof window !== 'undefined' && window.process && (window.process.type === 'renderer' || window.process.__nwjs)) {
		return true;
	}

	// Internet Explorer and Edge do not support colors.
	if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
		return false;
	}

	// Is webkit? http://stackoverflow.com/a/16459606/376773
	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
		// Is firebug? http://stackoverflow.com/a/398120/376773
		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
		// Is firefox >= v31?
		// https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31) ||
		// Double check webkit in userAgent just in case we are in a worker
		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
}

/**
 * Colorize log arguments if enabled.
 *
 * @api public
 */

function formatArgs(args) {
	args[0] = (this.useColors ? '%c' : '') +
		this.namespace +
		(this.useColors ? ' %c' : ' ') +
		args[0] +
		(this.useColors ? '%c ' : ' ') +
		'+' + module.exports.humanize(this.diff);

	if (!this.useColors) {
		return;
	}

	const c = 'color: ' + this.color;
	args.splice(1, 0, c, 'color: inherit');

	// The final "%c" is somewhat tricky, because there could be other
	// arguments passed either before or after the %c, so we need to
	// figure out the correct index to insert the CSS into
	let index = 0;
	let lastC = 0;
	args[0].replace(/%[a-zA-Z%]/g, match => {
		if (match === '%%') {
			return;
		}
		index++;
		if (match === '%c') {
			// We only are interested in the *last* %c
			// (the user may have provided their own)
			lastC = index;
		}
	});

	args.splice(lastC, 0, c);
}

/**
 * Invokes `console.log()` when available.
 * No-op when `console.log` is not a "function".
 *
 * @api public
 */
function log(...args) {
	// This hackery is required for IE8/9, where
	// the `console.log` function doesn't have 'apply'
	return typeof console === 'object' &&
		console.log &&
		console.log(...args);
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */
function save(namespaces) {
	try {
		if (namespaces) {
			exports.storage.setItem('debug', namespaces);
		} else {
			exports.storage.removeItem('debug');
		}
	} catch (error) {
		// Swallow
		// XXX (@Qix-) should we be logging these?
	}
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */
function load() {
	let r;
	try {
		r = exports.storage.getItem('debug');
	} catch (error) {
		// Swallow
		// XXX (@Qix-) should we be logging these?
	}

	// If debug isn't set in LS, and we're in Electron, try to load $DEBUG
	if (!r && typeof process !== 'undefined' && 'env' in process) {
		r = process.env.DEBUG;
	}

	return r;
}

/**
 * Localstorage attempts to return the localstorage.
 *
 * This is necessary because safari throws
 * when a user disables cookies/localstorage
 * and you attempt to access it.
 *
 * @return {LocalStorage}
 * @api private
 */

function localstorage() {
	try {
		// TVMLKit (Apple TV JS Runtime) does not have a window object, just localStorage in the global context
		// The Browser also has localStorage in the global context.
		return localStorage;
	} catch (error) {
		// Swallow
		// XXX (@Qix-) should we be logging these?
	}
}

module.exports = require('./common')(exports);

const {formatters} = module.exports;

/**
 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 */

formatters.j = function (v) {
	try {
		return JSON.stringify(v);
	} catch (error) {
		return '[UnexpectedJSONParseError]: ' + error.message;
	}
};

}).call(this)}).call(this,require('_process'))
},{"./common":25,"_process":40}],25:[function(require,module,exports){

/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 */

function setup(env) {
	createDebug.debug = createDebug;
	createDebug.default = createDebug;
	createDebug.coerce = coerce;
	createDebug.disable = disable;
	createDebug.enable = enable;
	createDebug.enabled = enabled;
	createDebug.humanize = require('ms');

	Object.keys(env).forEach(key => {
		createDebug[key] = env[key];
	});

	/**
	* Active `debug` instances.
	*/
	createDebug.instances = [];

	/**
	* The currently active debug mode names, and names to skip.
	*/

	createDebug.names = [];
	createDebug.skips = [];

	/**
	* Map of special "%n" handling functions, for the debug "format" argument.
	*
	* Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
	*/
	createDebug.formatters = {};

	/**
	* Selects a color for a debug namespace
	* @param {String} namespace The namespace string for the for the debug instance to be colored
	* @return {Number|String} An ANSI color code for the given namespace
	* @api private
	*/
	function selectColor(namespace) {
		let hash = 0;

		for (let i = 0; i < namespace.length; i++) {
			hash = ((hash << 5) - hash) + namespace.charCodeAt(i);
			hash |= 0; // Convert to 32bit integer
		}

		return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
	}
	createDebug.selectColor = selectColor;

	/**
	* Create a debugger with the given `namespace`.
	*
	* @param {String} namespace
	* @return {Function}
	* @api public
	*/
	function createDebug(namespace) {
		let prevTime;

		function debug(...args) {
			// Disabled?
			if (!debug.enabled) {
				return;
			}

			const self = debug;

			// Set `diff` timestamp
			const curr = Number(new Date());
			const ms = curr - (prevTime || curr);
			self.diff = ms;
			self.prev = prevTime;
			self.curr = curr;
			prevTime = curr;

			args[0] = createDebug.coerce(args[0]);

			if (typeof args[0] !== 'string') {
				// Anything else let's inspect with %O
				args.unshift('%O');
			}

			// Apply any `formatters` transformations
			let index = 0;
			args[0] = args[0].replace(/%([a-zA-Z%])/g, (match, format) => {
				// If we encounter an escaped % then don't increase the array index
				if (match === '%%') {
					return match;
				}
				index++;
				const formatter = createDebug.formatters[format];
				if (typeof formatter === 'function') {
					const val = args[index];
					match = formatter.call(self, val);

					// Now we need to remove `args[index]` since it's inlined in the `format`
					args.splice(index, 1);
					index--;
				}
				return match;
			});

			// Apply env-specific formatting (colors, etc.)
			createDebug.formatArgs.call(self, args);

			const logFn = self.log || createDebug.log;
			logFn.apply(self, args);
		}

		debug.namespace = namespace;
		debug.enabled = createDebug.enabled(namespace);
		debug.useColors = createDebug.useColors();
		debug.color = selectColor(namespace);
		debug.destroy = destroy;
		debug.extend = extend;
		// Debug.formatArgs = formatArgs;
		// debug.rawLog = rawLog;

		// env-specific initialization logic for debug instances
		if (typeof createDebug.init === 'function') {
			createDebug.init(debug);
		}

		createDebug.instances.push(debug);

		return debug;
	}

	function destroy() {
		const index = createDebug.instances.indexOf(this);
		if (index !== -1) {
			createDebug.instances.splice(index, 1);
			return true;
		}
		return false;
	}

	function extend(namespace, delimiter) {
		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
		newDebug.log = this.log;
		return newDebug;
	}

	/**
	* Enables a debug mode by namespaces. This can include modes
	* separated by a colon and wildcards.
	*
	* @param {String} namespaces
	* @api public
	*/
	function enable(namespaces) {
		createDebug.save(namespaces);

		createDebug.names = [];
		createDebug.skips = [];

		let i;
		const split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
		const len = split.length;

		for (i = 0; i < len; i++) {
			if (!split[i]) {
				// ignore empty strings
				continue;
			}

			namespaces = split[i].replace(/\*/g, '.*?');

			if (namespaces[0] === '-') {
				createDebug.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
			} else {
				createDebug.names.push(new RegExp('^' + namespaces + '$'));
			}
		}

		for (i = 0; i < createDebug.instances.length; i++) {
			const instance = createDebug.instances[i];
			instance.enabled = createDebug.enabled(instance.namespace);
		}
	}

	/**
	* Disable debug output.
	*
	* @return {String} namespaces
	* @api public
	*/
	function disable() {
		const namespaces = [
			...createDebug.names.map(toNamespace),
			...createDebug.skips.map(toNamespace).map(namespace => '-' + namespace)
		].join(',');
		createDebug.enable('');
		return namespaces;
	}

	/**
	* Returns true if the given mode name is enabled, false otherwise.
	*
	* @param {String} name
	* @return {Boolean}
	* @api public
	*/
	function enabled(name) {
		if (name[name.length - 1] === '*') {
			return true;
		}

		let i;
		let len;

		for (i = 0, len = createDebug.skips.length; i < len; i++) {
			if (createDebug.skips[i].test(name)) {
				return false;
			}
		}

		for (i = 0, len = createDebug.names.length; i < len; i++) {
			if (createDebug.names[i].test(name)) {
				return true;
			}
		}

		return false;
	}

	/**
	* Convert regexp to namespace
	*
	* @param {RegExp} regxep
	* @return {String} namespace
	* @api private
	*/
	function toNamespace(regexp) {
		return regexp.toString()
			.substring(2, regexp.toString().length - 2)
			.replace(/\.\*\?$/, '*');
	}

	/**
	* Coerce `val`.
	*
	* @param {Mixed} val
	* @return {Mixed}
	* @api private
	*/
	function coerce(val) {
		if (val instanceof Error) {
			return val.stack || val.message;
		}
		return val;
	}

	createDebug.enable(createDebug.load());

	return createDebug;
}

module.exports = setup;

},{"ms":26}],26:[function(require,module,exports){
/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var w = d * 7;
var y = d * 365.25;

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} [options]
 * @throws {Error} throw an error if val is not a non-empty string or a number
 * @return {String|Number}
 * @api public
 */

module.exports = function(val, options) {
  options = options || {};
  var type = typeof val;
  if (type === 'string' && val.length > 0) {
    return parse(val);
  } else if (type === 'number' && isFinite(val)) {
    return options.long ? fmtLong(val) : fmtShort(val);
  }
  throw new Error(
    'val is not a non-empty string or a valid number. val=' +
      JSON.stringify(val)
  );
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

function parse(str) {
  str = String(str);
  if (str.length > 100) {
    return;
  }
  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
    str
  );
  if (!match) {
    return;
  }
  var n = parseFloat(match[1]);
  var type = (match[2] || 'ms').toLowerCase();
  switch (type) {
    case 'years':
    case 'year':
    case 'yrs':
    case 'yr':
    case 'y':
      return n * y;
    case 'weeks':
    case 'week':
    case 'w':
      return n * w;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m;
    case 'seconds':
    case 'second':
    case 'secs':
    case 'sec':
    case 's':
      return n * s;
    case 'milliseconds':
    case 'millisecond':
    case 'msecs':
    case 'msec':
    case 'ms':
      return n;
    default:
      return undefined;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtShort(ms) {
  var msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return Math.round(ms / d) + 'd';
  }
  if (msAbs >= h) {
    return Math.round(ms / h) + 'h';
  }
  if (msAbs >= m) {
    return Math.round(ms / m) + 'm';
  }
  if (msAbs >= s) {
    return Math.round(ms / s) + 's';
  }
  return ms + 'ms';
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtLong(ms) {
  var msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return plural(ms, msAbs, d, 'day');
  }
  if (msAbs >= h) {
    return plural(ms, msAbs, h, 'hour');
  }
  if (msAbs >= m) {
    return plural(ms, msAbs, m, 'minute');
  }
  if (msAbs >= s) {
    return plural(ms, msAbs, s, 'second');
  }
  return ms + ' ms';
}

/**
 * Pluralization helper.
 */

function plural(ms, msAbs, n, name) {
  var isPlural = msAbs >= n * 1.5;
  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
}

},{}],27:[function(require,module,exports){
/**
 * Module dependencies.
 */

var keys = require('./keys');
var hasBinary = require('has-binary2');
var sliceBuffer = require('arraybuffer.slice');
var after = require('after');
var utf8 = require('./utf8');

var base64encoder;
if (typeof ArrayBuffer !== 'undefined') {
  base64encoder = require('base64-arraybuffer');
}

/**
 * Check if we are running an android browser. That requires us to use
 * ArrayBuffer with polling transports...
 *
 * http://ghinda.net/jpeg-blob-ajax-android/
 */

var isAndroid = typeof navigator !== 'undefined' && /Android/i.test(navigator.userAgent);

/**
 * Check if we are running in PhantomJS.
 * Uploading a Blob with PhantomJS does not work correctly, as reported here:
 * https://github.com/ariya/phantomjs/issues/11395
 * @type boolean
 */
var isPhantomJS = typeof navigator !== 'undefined' && /PhantomJS/i.test(navigator.userAgent);

/**
 * When true, avoids using Blobs to encode payloads.
 * @type boolean
 */
var dontSendBlobs = isAndroid || isPhantomJS;

/**
 * Current protocol version.
 */

exports.protocol = 3;

/**
 * Packet types.
 */

var packets = exports.packets = {
    open:     0    // non-ws
  , close:    1    // non-ws
  , ping:     2
  , pong:     3
  , message:  4
  , upgrade:  5
  , noop:     6
};

var packetslist = keys(packets);

/**
 * Premade error packet.
 */

var err = { type: 'error', data: 'parser error' };

/**
 * Create a blob api even for blob builder when vendor prefixes exist
 */

var Blob = require('blob');

/**
 * Encodes a packet.
 *
 *     <packet type id> [ <data> ]
 *
 * Example:
 *
 *     5hello world
 *     3
 *     4
 *
 * Binary is encoded in an identical principle
 *
 * @api private
 */

exports.encodePacket = function (packet, supportsBinary, utf8encode, callback) {
  if (typeof supportsBinary === 'function') {
    callback = supportsBinary;
    supportsBinary = false;
  }

  if (typeof utf8encode === 'function') {
    callback = utf8encode;
    utf8encode = null;
  }

  var data = (packet.data === undefined)
    ? undefined
    : packet.data.buffer || packet.data;

  if (typeof ArrayBuffer !== 'undefined' && data instanceof ArrayBuffer) {
    return encodeArrayBuffer(packet, supportsBinary, callback);
  } else if (typeof Blob !== 'undefined' && data instanceof Blob) {
    return encodeBlob(packet, supportsBinary, callback);
  }

  // might be an object with { base64: true, data: dataAsBase64String }
  if (data && data.base64) {
    return encodeBase64Object(packet, callback);
  }

  // Sending data as a utf-8 string
  var encoded = packets[packet.type];

  // data fragment is optional
  if (undefined !== packet.data) {
    encoded += utf8encode ? utf8.encode(String(packet.data), { strict: false }) : String(packet.data);
  }

  return callback('' + encoded);

};

function encodeBase64Object(packet, callback) {
  // packet data is an object { base64: true, data: dataAsBase64String }
  var message = 'b' + exports.packets[packet.type] + packet.data.data;
  return callback(message);
}

/**
 * Encode packet helpers for binary types
 */

function encodeArrayBuffer(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  var data = packet.data;
  var contentArray = new Uint8Array(data);
  var resultBuffer = new Uint8Array(1 + data.byteLength);

  resultBuffer[0] = packets[packet.type];
  for (var i = 0; i < contentArray.length; i++) {
    resultBuffer[i+1] = contentArray[i];
  }

  return callback(resultBuffer.buffer);
}

function encodeBlobAsArrayBuffer(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  var fr = new FileReader();
  fr.onload = function() {
    exports.encodePacket({ type: packet.type, data: fr.result }, supportsBinary, true, callback);
  };
  return fr.readAsArrayBuffer(packet.data);
}

function encodeBlob(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  if (dontSendBlobs) {
    return encodeBlobAsArrayBuffer(packet, supportsBinary, callback);
  }

  var length = new Uint8Array(1);
  length[0] = packets[packet.type];
  var blob = new Blob([length.buffer, packet.data]);

  return callback(blob);
}

/**
 * Encodes a packet with binary data in a base64 string
 *
 * @param {Object} packet, has `type` and `data`
 * @return {String} base64 encoded message
 */

exports.encodeBase64Packet = function(packet, callback) {
  var message = 'b' + exports.packets[packet.type];
  if (typeof Blob !== 'undefined' && packet.data instanceof Blob) {
    var fr = new FileReader();
    fr.onload = function() {
      var b64 = fr.result.split(',')[1];
      callback(message + b64);
    };
    return fr.readAsDataURL(packet.data);
  }

  var b64data;
  try {
    b64data = String.fromCharCode.apply(null, new Uint8Array(packet.data));
  } catch (e) {
    // iPhone Safari doesn't let you apply with typed arrays
    var typed = new Uint8Array(packet.data);
    var basic = new Array(typed.length);
    for (var i = 0; i < typed.length; i++) {
      basic[i] = typed[i];
    }
    b64data = String.fromCharCode.apply(null, basic);
  }
  message += btoa(b64data);
  return callback(message);
};

/**
 * Decodes a packet. Changes format to Blob if requested.
 *
 * @return {Object} with `type` and `data` (if any)
 * @api private
 */

exports.decodePacket = function (data, binaryType, utf8decode) {
  if (data === undefined) {
    return err;
  }
  // String data
  if (typeof data === 'string') {
    if (data.charAt(0) === 'b') {
      return exports.decodeBase64Packet(data.substr(1), binaryType);
    }

    if (utf8decode) {
      data = tryDecode(data);
      if (data === false) {
        return err;
      }
    }
    var type = data.charAt(0);

    if (Number(type) != type || !packetslist[type]) {
      return err;
    }

    if (data.length > 1) {
      return { type: packetslist[type], data: data.substring(1) };
    } else {
      return { type: packetslist[type] };
    }
  }

  var asArray = new Uint8Array(data);
  var type = asArray[0];
  var rest = sliceBuffer(data, 1);
  if (Blob && binaryType === 'blob') {
    rest = new Blob([rest]);
  }
  return { type: packetslist[type], data: rest };
};

function tryDecode(data) {
  try {
    data = utf8.decode(data, { strict: false });
  } catch (e) {
    return false;
  }
  return data;
}

/**
 * Decodes a packet encoded in a base64 string
 *
 * @param {String} base64 encoded message
 * @return {Object} with `type` and `data` (if any)
 */

exports.decodeBase64Packet = function(msg, binaryType) {
  var type = packetslist[msg.charAt(0)];
  if (!base64encoder) {
    return { type: type, data: { base64: true, data: msg.substr(1) } };
  }

  var data = base64encoder.decode(msg.substr(1));

  if (binaryType === 'blob' && Blob) {
    data = new Blob([data]);
  }

  return { type: type, data: data };
};

/**
 * Encodes multiple messages (payload).
 *
 *     <length>:data
 *
 * Example:
 *
 *     11:hello world2:hi
 *
 * If any contents are binary, they will be encoded as base64 strings. Base64
 * encoded strings are marked with a b before the length specifier
 *
 * @param {Array} packets
 * @api private
 */

exports.encodePayload = function (packets, supportsBinary, callback) {
  if (typeof supportsBinary === 'function') {
    callback = supportsBinary;
    supportsBinary = null;
  }

  var isBinary = hasBinary(packets);

  if (supportsBinary && isBinary) {
    if (Blob && !dontSendBlobs) {
      return exports.encodePayloadAsBlob(packets, callback);
    }

    return exports.encodePayloadAsArrayBuffer(packets, callback);
  }

  if (!packets.length) {
    return callback('0:');
  }

  function setLengthHeader(message) {
    return message.length + ':' + message;
  }

  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, !isBinary ? false : supportsBinary, false, function(message) {
      doneCallback(null, setLengthHeader(message));
    });
  }

  map(packets, encodeOne, function(err, results) {
    return callback(results.join(''));
  });
};

/**
 * Async array map using after
 */

function map(ary, each, done) {
  var result = new Array(ary.length);
  var next = after(ary.length, done);

  var eachWithIndex = function(i, el, cb) {
    each(el, function(error, msg) {
      result[i] = msg;
      cb(error, result);
    });
  };

  for (var i = 0; i < ary.length; i++) {
    eachWithIndex(i, ary[i], next);
  }
}

/*
 * Decodes data when a payload is maybe expected. Possible binary contents are
 * decoded from their base64 representation
 *
 * @param {String} data, callback method
 * @api public
 */

exports.decodePayload = function (data, binaryType, callback) {
  if (typeof data !== 'string') {
    return exports.decodePayloadAsBinary(data, binaryType, callback);
  }

  if (typeof binaryType === 'function') {
    callback = binaryType;
    binaryType = null;
  }

  var packet;
  if (data === '') {
    // parser error - ignoring payload
    return callback(err, 0, 1);
  }

  var length = '', n, msg;

  for (var i = 0, l = data.length; i < l; i++) {
    var chr = data.charAt(i);

    if (chr !== ':') {
      length += chr;
      continue;
    }

    if (length === '' || (length != (n = Number(length)))) {
      // parser error - ignoring payload
      return callback(err, 0, 1);
    }

    msg = data.substr(i + 1, n);

    if (length != msg.length) {
      // parser error - ignoring payload
      return callback(err, 0, 1);
    }

    if (msg.length) {
      packet = exports.decodePacket(msg, binaryType, false);

      if (err.type === packet.type && err.data === packet.data) {
        // parser error in individual packet - ignoring payload
        return callback(err, 0, 1);
      }

      var ret = callback(packet, i + n, l);
      if (false === ret) return;
    }

    // advance cursor
    i += n;
    length = '';
  }

  if (length !== '') {
    // parser error - ignoring payload
    return callback(err, 0, 1);
  }

};

/**
 * Encodes multiple messages (payload) as binary.
 *
 * <1 = binary, 0 = string><number from 0-9><number from 0-9>[...]<number
 * 255><data>
 *
 * Example:
 * 1 3 255 1 2 3, if the binary contents are interpreted as 8 bit integers
 *
 * @param {Array} packets
 * @return {ArrayBuffer} encoded payload
 * @api private
 */

exports.encodePayloadAsArrayBuffer = function(packets, callback) {
  if (!packets.length) {
    return callback(new ArrayBuffer(0));
  }

  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, true, true, function(data) {
      return doneCallback(null, data);
    });
  }

  map(packets, encodeOne, function(err, encodedPackets) {
    var totalLength = encodedPackets.reduce(function(acc, p) {
      var len;
      if (typeof p === 'string'){
        len = p.length;
      } else {
        len = p.byteLength;
      }
      return acc + len.toString().length + len + 2; // string/binary identifier + separator = 2
    }, 0);

    var resultArray = new Uint8Array(totalLength);

    var bufferIndex = 0;
    encodedPackets.forEach(function(p) {
      var isString = typeof p === 'string';
      var ab = p;
      if (isString) {
        var view = new Uint8Array(p.length);
        for (var i = 0; i < p.length; i++) {
          view[i] = p.charCodeAt(i);
        }
        ab = view.buffer;
      }

      if (isString) { // not true binary
        resultArray[bufferIndex++] = 0;
      } else { // true binary
        resultArray[bufferIndex++] = 1;
      }

      var lenStr = ab.byteLength.toString();
      for (var i = 0; i < lenStr.length; i++) {
        resultArray[bufferIndex++] = parseInt(lenStr[i]);
      }
      resultArray[bufferIndex++] = 255;

      var view = new Uint8Array(ab);
      for (var i = 0; i < view.length; i++) {
        resultArray[bufferIndex++] = view[i];
      }
    });

    return callback(resultArray.buffer);
  });
};

/**
 * Encode as Blob
 */

exports.encodePayloadAsBlob = function(packets, callback) {
  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, true, true, function(encoded) {
      var binaryIdentifier = new Uint8Array(1);
      binaryIdentifier[0] = 1;
      if (typeof encoded === 'string') {
        var view = new Uint8Array(encoded.length);
        for (var i = 0; i < encoded.length; i++) {
          view[i] = encoded.charCodeAt(i);
        }
        encoded = view.buffer;
        binaryIdentifier[0] = 0;
      }

      var len = (encoded instanceof ArrayBuffer)
        ? encoded.byteLength
        : encoded.size;

      var lenStr = len.toString();
      var lengthAry = new Uint8Array(lenStr.length + 1);
      for (var i = 0; i < lenStr.length; i++) {
        lengthAry[i] = parseInt(lenStr[i]);
      }
      lengthAry[lenStr.length] = 255;

      if (Blob) {
        var blob = new Blob([binaryIdentifier.buffer, lengthAry.buffer, encoded]);
        doneCallback(null, blob);
      }
    });
  }

  map(packets, encodeOne, function(err, results) {
    return callback(new Blob(results));
  });
};

/*
 * Decodes data when a payload is maybe expected. Strings are decoded by
 * interpreting each byte as a key code for entries marked to start with 0. See
 * description of encodePayloadAsBinary
 *
 * @param {ArrayBuffer} data, callback method
 * @api public
 */

exports.decodePayloadAsBinary = function (data, binaryType, callback) {
  if (typeof binaryType === 'function') {
    callback = binaryType;
    binaryType = null;
  }

  var bufferTail = data;
  var buffers = [];

  while (bufferTail.byteLength > 0) {
    var tailArray = new Uint8Array(bufferTail);
    var isString = tailArray[0] === 0;
    var msgLength = '';

    for (var i = 1; ; i++) {
      if (tailArray[i] === 255) break;

      // 310 = char length of Number.MAX_VALUE
      if (msgLength.length > 310) {
        return callback(err, 0, 1);
      }

      msgLength += tailArray[i];
    }

    bufferTail = sliceBuffer(bufferTail, 2 + msgLength.length);
    msgLength = parseInt(msgLength);

    var msg = sliceBuffer(bufferTail, 0, msgLength);
    if (isString) {
      try {
        msg = String.fromCharCode.apply(null, new Uint8Array(msg));
      } catch (e) {
        // iPhone Safari doesn't let you apply to typed arrays
        var typed = new Uint8Array(msg);
        msg = '';
        for (var i = 0; i < typed.length; i++) {
          msg += String.fromCharCode(typed[i]);
        }
      }
    }

    buffers.push(msg);
    bufferTail = sliceBuffer(bufferTail, msgLength);
  }

  var total = buffers.length;
  buffers.forEach(function(buffer, i) {
    callback(exports.decodePacket(buffer, binaryType, true), i, total);
  });
};

},{"./keys":28,"./utf8":29,"after":2,"arraybuffer.slice":3,"base64-arraybuffer":5,"blob":7,"has-binary2":32}],28:[function(require,module,exports){

/**
 * Gets the keys for an object.
 *
 * @return {Array} keys
 * @api private
 */

module.exports = Object.keys || function keys (obj){
  var arr = [];
  var has = Object.prototype.hasOwnProperty;

  for (var i in obj) {
    if (has.call(obj, i)) {
      arr.push(i);
    }
  }
  return arr;
};

},{}],29:[function(require,module,exports){
/*! https://mths.be/utf8js v2.1.2 by @mathias */

var stringFromCharCode = String.fromCharCode;

// Taken from https://mths.be/punycode
function ucs2decode(string) {
	var output = [];
	var counter = 0;
	var length = string.length;
	var value;
	var extra;
	while (counter < length) {
		value = string.charCodeAt(counter++);
		if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
			// high surrogate, and there is a next character
			extra = string.charCodeAt(counter++);
			if ((extra & 0xFC00) == 0xDC00) { // low surrogate
				output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
			} else {
				// unmatched surrogate; only append this code unit, in case the next
				// code unit is the high surrogate of a surrogate pair
				output.push(value);
				counter--;
			}
		} else {
			output.push(value);
		}
	}
	return output;
}

// Taken from https://mths.be/punycode
function ucs2encode(array) {
	var length = array.length;
	var index = -1;
	var value;
	var output = '';
	while (++index < length) {
		value = array[index];
		if (value > 0xFFFF) {
			value -= 0x10000;
			output += stringFromCharCode(value >>> 10 & 0x3FF | 0xD800);
			value = 0xDC00 | value & 0x3FF;
		}
		output += stringFromCharCode(value);
	}
	return output;
}

function checkScalarValue(codePoint, strict) {
	if (codePoint >= 0xD800 && codePoint <= 0xDFFF) {
		if (strict) {
			throw Error(
				'Lone surrogate U+' + codePoint.toString(16).toUpperCase() +
				' is not a scalar value'
			);
		}
		return false;
	}
	return true;
}
/*--------------------------------------------------------------------------*/

function createByte(codePoint, shift) {
	return stringFromCharCode(((codePoint >> shift) & 0x3F) | 0x80);
}

function encodeCodePoint(codePoint, strict) {
	if ((codePoint & 0xFFFFFF80) == 0) { // 1-byte sequence
		return stringFromCharCode(codePoint);
	}
	var symbol = '';
	if ((codePoint & 0xFFFFF800) == 0) { // 2-byte sequence
		symbol = stringFromCharCode(((codePoint >> 6) & 0x1F) | 0xC0);
	}
	else if ((codePoint & 0xFFFF0000) == 0) { // 3-byte sequence
		if (!checkScalarValue(codePoint, strict)) {
			codePoint = 0xFFFD;
		}
		symbol = stringFromCharCode(((codePoint >> 12) & 0x0F) | 0xE0);
		symbol += createByte(codePoint, 6);
	}
	else if ((codePoint & 0xFFE00000) == 0) { // 4-byte sequence
		symbol = stringFromCharCode(((codePoint >> 18) & 0x07) | 0xF0);
		symbol += createByte(codePoint, 12);
		symbol += createByte(codePoint, 6);
	}
	symbol += stringFromCharCode((codePoint & 0x3F) | 0x80);
	return symbol;
}

function utf8encode(string, opts) {
	opts = opts || {};
	var strict = false !== opts.strict;

	var codePoints = ucs2decode(string);
	var length = codePoints.length;
	var index = -1;
	var codePoint;
	var byteString = '';
	while (++index < length) {
		codePoint = codePoints[index];
		byteString += encodeCodePoint(codePoint, strict);
	}
	return byteString;
}

/*--------------------------------------------------------------------------*/

function readContinuationByte() {
	if (byteIndex >= byteCount) {
		throw Error('Invalid byte index');
	}

	var continuationByte = byteArray[byteIndex] & 0xFF;
	byteIndex++;

	if ((continuationByte & 0xC0) == 0x80) {
		return continuationByte & 0x3F;
	}

	// If we end up here, it’s not a continuation byte
	throw Error('Invalid continuation byte');
}

function decodeSymbol(strict) {
	var byte1;
	var byte2;
	var byte3;
	var byte4;
	var codePoint;

	if (byteIndex > byteCount) {
		throw Error('Invalid byte index');
	}

	if (byteIndex == byteCount) {
		return false;
	}

	// Read first byte
	byte1 = byteArray[byteIndex] & 0xFF;
	byteIndex++;

	// 1-byte sequence (no continuation bytes)
	if ((byte1 & 0x80) == 0) {
		return byte1;
	}

	// 2-byte sequence
	if ((byte1 & 0xE0) == 0xC0) {
		byte2 = readContinuationByte();
		codePoint = ((byte1 & 0x1F) << 6) | byte2;
		if (codePoint >= 0x80) {
			return codePoint;
		} else {
			throw Error('Invalid continuation byte');
		}
	}

	// 3-byte sequence (may include unpaired surrogates)
	if ((byte1 & 0xF0) == 0xE0) {
		byte2 = readContinuationByte();
		byte3 = readContinuationByte();
		codePoint = ((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3;
		if (codePoint >= 0x0800) {
			return checkScalarValue(codePoint, strict) ? codePoint : 0xFFFD;
		} else {
			throw Error('Invalid continuation byte');
		}
	}

	// 4-byte sequence
	if ((byte1 & 0xF8) == 0xF0) {
		byte2 = readContinuationByte();
		byte3 = readContinuationByte();
		byte4 = readContinuationByte();
		codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) |
			(byte3 << 0x06) | byte4;
		if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
			return codePoint;
		}
	}

	throw Error('Invalid UTF-8 detected');
}

var byteArray;
var byteCount;
var byteIndex;
function utf8decode(byteString, opts) {
	opts = opts || {};
	var strict = false !== opts.strict;

	byteArray = ucs2decode(byteString);
	byteCount = byteArray.length;
	byteIndex = 0;
	var codePoints = [];
	var tmp;
	while ((tmp = decodeSymbol(strict)) !== false) {
		codePoints.push(tmp);
	}
	return ucs2encode(codePoints);
}

module.exports = {
	version: '2.1.2',
	encode: utf8encode,
	decode: utf8decode
};

},{}],30:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';

var R = typeof Reflect === 'object' ? Reflect : null
var ReflectApply = R && typeof R.apply === 'function'
  ? R.apply
  : function ReflectApply(target, receiver, args) {
    return Function.prototype.apply.call(target, receiver, args);
  }

var ReflectOwnKeys
if (R && typeof R.ownKeys === 'function') {
  ReflectOwnKeys = R.ownKeys
} else if (Object.getOwnPropertySymbols) {
  ReflectOwnKeys = function ReflectOwnKeys(target) {
    return Object.getOwnPropertyNames(target)
      .concat(Object.getOwnPropertySymbols(target));
  };
} else {
  ReflectOwnKeys = function ReflectOwnKeys(target) {
    return Object.getOwnPropertyNames(target);
  };
}

function ProcessEmitWarning(warning) {
  if (console && console.warn) console.warn(warning);
}

var NumberIsNaN = Number.isNaN || function NumberIsNaN(value) {
  return value !== value;
}

function EventEmitter() {
  EventEmitter.init.call(this);
}
module.exports = EventEmitter;
module.exports.once = once;

// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;

EventEmitter.prototype._events = undefined;
EventEmitter.prototype._eventsCount = 0;
EventEmitter.prototype._maxListeners = undefined;

// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
var defaultMaxListeners = 10;

function checkListener(listener) {
  if (typeof listener !== 'function') {
    throw new TypeError('The "listener" argument must be of type Function. Received type ' + typeof listener);
  }
}

Object.defineProperty(EventEmitter, 'defaultMaxListeners', {
  enumerable: true,
  get: function() {
    return defaultMaxListeners;
  },
  set: function(arg) {
    if (typeof arg !== 'number' || arg < 0 || NumberIsNaN(arg)) {
      throw new RangeError('The value of "defaultMaxListeners" is out of range. It must be a non-negative number. Received ' + arg + '.');
    }
    defaultMaxListeners = arg;
  }
});

EventEmitter.init = function() {

  if (this._events === undefined ||
      this._events === Object.getPrototypeOf(this)._events) {
    this._events = Object.create(null);
    this._eventsCount = 0;
  }

  this._maxListeners = this._maxListeners || undefined;
};

// Obviously not all Emitters should be limited to 10. This function allows
// that to be increased. Set to zero for unlimited.
EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {
  if (typeof n !== 'number' || n < 0 || NumberIsNaN(n)) {
    throw new RangeError('The value of "n" is out of range. It must be a non-negative number. Received ' + n + '.');
  }
  this._maxListeners = n;
  return this;
};

function _getMaxListeners(that) {
  if (that._maxListeners === undefined)
    return EventEmitter.defaultMaxListeners;
  return that._maxListeners;
}

EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
  return _getMaxListeners(this);
};

EventEmitter.prototype.emit = function emit(type) {
  var args = [];
  for (var i = 1; i < arguments.length; i++) args.push(arguments[i]);
  var doError = (type === 'error');

  var events = this._events;
  if (events !== undefined)
    doError = (doError && events.error === undefined);
  else if (!doError)
    return false;

  // If there is no 'error' event listener then throw.
  if (doError) {
    var er;
    if (args.length > 0)
      er = args[0];
    if (er instanceof Error) {
      // Note: The comments on the `throw` lines are intentional, they show
      // up in Node's output if this results in an unhandled exception.
      throw er; // Unhandled 'error' event
    }
    // At least give some kind of context to the user
    var err = new Error('Unhandled error.' + (er ? ' (' + er.message + ')' : ''));
    err.context = er;
    throw err; // Unhandled 'error' event
  }

  var handler = events[type];

  if (handler === undefined)
    return false;

  if (typeof handler === 'function') {
    ReflectApply(handler, this, args);
  } else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      ReflectApply(listeners[i], this, args);
  }

  return true;
};

function _addListener(target, type, listener, prepend) {
  var m;
  var events;
  var existing;

  checkListener(listener);

  events = target._events;
  if (events === undefined) {
    events = target._events = Object.create(null);
    target._eventsCount = 0;
  } else {
    // To avoid recursion in the case that type === "newListener"! Before
    // adding it to the listeners, first emit "newListener".
    if (events.newListener !== undefined) {
      target.emit('newListener', type,
                  listener.listener ? listener.listener : listener);

      // Re-assign `events` because a newListener handler could have caused the
      // this._events to be assigned to a new object
      events = target._events;
    }
    existing = events[type];
  }

  if (existing === undefined) {
    // Optimize the case of one listener. Don't need the extra array object.
    existing = events[type] = listener;
    ++target._eventsCount;
  } else {
    if (typeof existing === 'function') {
      // Adding the second element, need to change to array.
      existing = events[type] =
        prepend ? [listener, existing] : [existing, listener];
      // If we've already got an array, just append.
    } else if (prepend) {
      existing.unshift(listener);
    } else {
      existing.push(listener);
    }

    // Check for listener leak
    m = _getMaxListeners(target);
    if (m > 0 && existing.length > m && !existing.warned) {
      existing.warned = true;
      // No error code for this since it is a Warning
      // eslint-disable-next-line no-restricted-syntax
      var w = new Error('Possible EventEmitter memory leak detected. ' +
                          existing.length + ' ' + String(type) + ' listeners ' +
                          'added. Use emitter.setMaxListeners() to ' +
                          'increase limit');
      w.name = 'MaxListenersExceededWarning';
      w.emitter = target;
      w.type = type;
      w.count = existing.length;
      ProcessEmitWarning(w);
    }
  }

  return target;
}

EventEmitter.prototype.addListener = function addListener(type, listener) {
  return _addListener(this, type, listener, false);
};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.prependListener =
    function prependListener(type, listener) {
      return _addListener(this, type, listener, true);
    };

function onceWrapper() {
  if (!this.fired) {
    this.target.removeListener(this.type, this.wrapFn);
    this.fired = true;
    if (arguments.length === 0)
      return this.listener.call(this.target);
    return this.listener.apply(this.target, arguments);
  }
}

function _onceWrap(target, type, listener) {
  var state = { fired: false, wrapFn: undefined, target: target, type: type, listener: listener };
  var wrapped = onceWrapper.bind(state);
  wrapped.listener = listener;
  state.wrapFn = wrapped;
  return wrapped;
}

EventEmitter.prototype.once = function once(type, listener) {
  checkListener(listener);
  this.on(type, _onceWrap(this, type, listener));
  return this;
};

EventEmitter.prototype.prependOnceListener =
    function prependOnceListener(type, listener) {
      checkListener(listener);
      this.prependListener(type, _onceWrap(this, type, listener));
      return this;
    };

// Emits a 'removeListener' event if and only if the listener was removed.
EventEmitter.prototype.removeListener =
    function removeListener(type, listener) {
      var list, events, position, i, originalListener;

      checkListener(listener);

      events = this._events;
      if (events === undefined)
        return this;

      list = events[type];
      if (list === undefined)
        return this;

      if (list === listener || list.listener === listener) {
        if (--this._eventsCount === 0)
          this._events = Object.create(null);
        else {
          delete events[type];
          if (events.removeListener)
            this.emit('removeListener', type, list.listener || listener);
        }
      } else if (typeof list !== 'function') {
        position = -1;

        for (i = list.length - 1; i >= 0; i--) {
          if (list[i] === listener || list[i].listener === listener) {
            originalListener = list[i].listener;
            position = i;
            break;
          }
        }

        if (position < 0)
          return this;

        if (position === 0)
          list.shift();
        else {
          spliceOne(list, position);
        }

        if (list.length === 1)
          events[type] = list[0];

        if (events.removeListener !== undefined)
          this.emit('removeListener', type, originalListener || listener);
      }

      return this;
    };

EventEmitter.prototype.off = EventEmitter.prototype.removeListener;

EventEmitter.prototype.removeAllListeners =
    function removeAllListeners(type) {
      var listeners, events, i;

      events = this._events;
      if (events === undefined)
        return this;

      // not listening for removeListener, no need to emit
      if (events.removeListener === undefined) {
        if (arguments.length === 0) {
          this._events = Object.create(null);
          this._eventsCount = 0;
        } else if (events[type] !== undefined) {
          if (--this._eventsCount === 0)
            this._events = Object.create(null);
          else
            delete events[type];
        }
        return this;
      }

      // emit removeListener for all listeners on all events
      if (arguments.length === 0) {
        var keys = Object.keys(events);
        var key;
        for (i = 0; i < keys.length; ++i) {
          key = keys[i];
          if (key === 'removeListener') continue;
          this.removeAllListeners(key);
        }
        this.removeAllListeners('removeListener');
        this._events = Object.create(null);
        this._eventsCount = 0;
        return this;
      }

      listeners = events[type];

      if (typeof listeners === 'function') {
        this.removeListener(type, listeners);
      } else if (listeners !== undefined) {
        // LIFO order
        for (i = listeners.length - 1; i >= 0; i--) {
          this.removeListener(type, listeners[i]);
        }
      }

      return this;
    };

function _listeners(target, type, unwrap) {
  var events = target._events;

  if (events === undefined)
    return [];

  var evlistener = events[type];
  if (evlistener === undefined)
    return [];

  if (typeof evlistener === 'function')
    return unwrap ? [evlistener.listener || evlistener] : [evlistener];

  return unwrap ?
    unwrapListeners(evlistener) : arrayClone(evlistener, evlistener.length);
}

EventEmitter.prototype.listeners = function listeners(type) {
  return _listeners(this, type, true);
};

EventEmitter.prototype.rawListeners = function rawListeners(type) {
  return _listeners(this, type, false);
};

EventEmitter.listenerCount = function(emitter, type) {
  if (typeof emitter.listenerCount === 'function') {
    return emitter.listenerCount(type);
  } else {
    return listenerCount.call(emitter, type);
  }
};

EventEmitter.prototype.listenerCount = listenerCount;
function listenerCount(type) {
  var events = this._events;

  if (events !== undefined) {
    var evlistener = events[type];

    if (typeof evlistener === 'function') {
      return 1;
    } else if (evlistener !== undefined) {
      return evlistener.length;
    }
  }

  return 0;
}

EventEmitter.prototype.eventNames = function eventNames() {
  return this._eventsCount > 0 ? ReflectOwnKeys(this._events) : [];
};

function arrayClone(arr, n) {
  var copy = new Array(n);
  for (var i = 0; i < n; ++i)
    copy[i] = arr[i];
  return copy;
}

function spliceOne(list, index) {
  for (; index + 1 < list.length; index++)
    list[index] = list[index + 1];
  list.pop();
}

function unwrapListeners(arr) {
  var ret = new Array(arr.length);
  for (var i = 0; i < ret.length; ++i) {
    ret[i] = arr[i].listener || arr[i];
  }
  return ret;
}

function once(emitter, name) {
  return new Promise(function (resolve, reject) {
    function eventListener() {
      if (errorListener !== undefined) {
        emitter.removeListener('error', errorListener);
      }
      resolve([].slice.call(arguments));
    };
    var errorListener;

    // Adding an error listener is not optional because
    // if an error is thrown on an event emitter we cannot
    // guarantee that the actual event we are waiting will
    // be fired. The result could be a silent way to create
    // memory or file descriptor leaks, which is something
    // we should avoid.
    if (name !== 'error') {
      errorListener = function errorListener(err) {
        emitter.removeListener(name, eventListener);
        reject(err);
      };

      emitter.once('error', errorListener);
    }

    emitter.once(name, eventListener);
  });
}

},{}],31:[function(require,module,exports){
// originally pulled out of simple-peer

module.exports = function getBrowserRTC () {
  if (typeof window === 'undefined') return null
  var wrtc = {
    RTCPeerConnection: window.RTCPeerConnection || window.mozRTCPeerConnection ||
      window.webkitRTCPeerConnection,
    RTCSessionDescription: window.RTCSessionDescription ||
      window.mozRTCSessionDescription || window.webkitRTCSessionDescription,
    RTCIceCandidate: window.RTCIceCandidate || window.mozRTCIceCandidate ||
      window.webkitRTCIceCandidate
  }
  if (!wrtc.RTCPeerConnection) return null
  return wrtc
}

},{}],32:[function(require,module,exports){
(function (Buffer){(function (){
/* global Blob File */

/*
 * Module requirements.
 */

var isArray = require('isarray');

var toString = Object.prototype.toString;
var withNativeBlob = typeof Blob === 'function' ||
                        typeof Blob !== 'undefined' && toString.call(Blob) === '[object BlobConstructor]';
var withNativeFile = typeof File === 'function' ||
                        typeof File !== 'undefined' && toString.call(File) === '[object FileConstructor]';

/**
 * Module exports.
 */

module.exports = hasBinary;

/**
 * Checks for binary data.
 *
 * Supports Buffer, ArrayBuffer, Blob and File.
 *
 * @param {Object} anything
 * @api public
 */

function hasBinary (obj) {
  if (!obj || typeof obj !== 'object') {
    return false;
  }

  if (isArray(obj)) {
    for (var i = 0, l = obj.length; i < l; i++) {
      if (hasBinary(obj[i])) {
        return true;
      }
    }
    return false;
  }

  if ((typeof Buffer === 'function' && Buffer.isBuffer && Buffer.isBuffer(obj)) ||
    (typeof ArrayBuffer === 'function' && obj instanceof ArrayBuffer) ||
    (withNativeBlob && obj instanceof Blob) ||
    (withNativeFile && obj instanceof File)
  ) {
    return true;
  }

  // see: https://github.com/Automattic/has-binary/pull/4
  if (obj.toJSON && typeof obj.toJSON === 'function' && arguments.length === 1) {
    return hasBinary(obj.toJSON(), true);
  }

  for (var key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key) && hasBinary(obj[key])) {
      return true;
    }
  }

  return false;
}

}).call(this)}).call(this,require("buffer").Buffer)
},{"buffer":9,"isarray":37}],33:[function(require,module,exports){

/**
 * Module exports.
 *
 * Logic borrowed from Modernizr:
 *
 *   - https://github.com/Modernizr/Modernizr/blob/master/feature-detects/cors.js
 */

try {
  module.exports = typeof XMLHttpRequest !== 'undefined' &&
    'withCredentials' in new XMLHttpRequest();
} catch (err) {
  // if XMLHttp support is disabled in IE then it will throw
  // when trying to create
  module.exports = false;
}

},{}],34:[function(require,module,exports){
exports.read = function (buffer, offset, isLE, mLen, nBytes) {
  var e, m
  var eLen = (nBytes * 8) - mLen - 1
  var eMax = (1 << eLen) - 1
  var eBias = eMax >> 1
  var nBits = -7
  var i = isLE ? (nBytes - 1) : 0
  var d = isLE ? -1 : 1
  var s = buffer[offset + i]

  i += d

  e = s & ((1 << (-nBits)) - 1)
  s >>= (-nBits)
  nBits += eLen
  for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {}

  m = e & ((1 << (-nBits)) - 1)
  e >>= (-nBits)
  nBits += mLen
  for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {}

  if (e === 0) {
    e = 1 - eBias
  } else if (e === eMax) {
    return m ? NaN : ((s ? -1 : 1) * Infinity)
  } else {
    m = m + Math.pow(2, mLen)
    e = e - eBias
  }
  return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
}

exports.write = function (buffer, value, offset, isLE, mLen, nBytes) {
  var e, m, c
  var eLen = (nBytes * 8) - mLen - 1
  var eMax = (1 << eLen) - 1
  var eBias = eMax >> 1
  var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0)
  var i = isLE ? 0 : (nBytes - 1)
  var d = isLE ? 1 : -1
  var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0

  value = Math.abs(value)

  if (isNaN(value) || value === Infinity) {
    m = isNaN(value) ? 1 : 0
    e = eMax
  } else {
    e = Math.floor(Math.log(value) / Math.LN2)
    if (value * (c = Math.pow(2, -e)) < 1) {
      e--
      c *= 2
    }
    if (e + eBias >= 1) {
      value += rt / c
    } else {
      value += rt * Math.pow(2, 1 - eBias)
    }
    if (value * c >= 2) {
      e++
      c /= 2
    }

    if (e + eBias >= eMax) {
      m = 0
      e = eMax
    } else if (e + eBias >= 1) {
      m = ((value * c) - 1) * Math.pow(2, mLen)
      e = e + eBias
    } else {
      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen)
      e = 0
    }
  }

  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}

  e = (e << mLen) | m
  eLen += mLen
  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}

  buffer[offset + i - d] |= s * 128
}

},{}],35:[function(require,module,exports){

var indexOf = [].indexOf;

module.exports = function(arr, obj){
  if (indexOf) return arr.indexOf(obj);
  for (var i = 0; i < arr.length; ++i) {
    if (arr[i] === obj) return i;
  }
  return -1;
};
},{}],36:[function(require,module,exports){
if (typeof Object.create === 'function') {
  // implementation from standard node.js 'util' module
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  };
} else {
  // old school shim for old browsers
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    var TempCtor = function () {}
    TempCtor.prototype = superCtor.prototype
    ctor.prototype = new TempCtor()
    ctor.prototype.constructor = ctor
  }
}

},{}],37:[function(require,module,exports){
var toString = {}.toString;

module.exports = Array.isArray || function (arr) {
  return toString.call(arr) == '[object Array]';
};

},{}],38:[function(require,module,exports){
/**
 * Compiles a querystring
 * Returns string representation of the object
 *
 * @param {Object}
 * @api private
 */

exports.encode = function (obj) {
  var str = '';

  for (var i in obj) {
    if (obj.hasOwnProperty(i)) {
      if (str.length) str += '&';
      str += encodeURIComponent(i) + '=' + encodeURIComponent(obj[i]);
    }
  }

  return str;
};

/**
 * Parses a simple querystring into an object
 *
 * @param {String} qs
 * @api private
 */

exports.decode = function(qs){
  var qry = {};
  var pairs = qs.split('&');
  for (var i = 0, l = pairs.length; i < l; i++) {
    var pair = pairs[i].split('=');
    qry[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
  }
  return qry;
};

},{}],39:[function(require,module,exports){
/**
 * Parses an URI
 *
 * @author Steven Levithan <stevenlevithan.com> (MIT license)
 * @api private
 */

var re = /^(?:(?![^:@]+:[^:@\/]*@)(http|https|ws|wss):\/\/)?((?:(([^:@]*)(?::([^:@]*))?)?@)?((?:[a-f0-9]{0,4}:){2,7}[a-f0-9]{0,4}|[^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/;

var parts = [
    'source', 'protocol', 'authority', 'userInfo', 'user', 'password', 'host', 'port', 'relative', 'path', 'directory', 'file', 'query', 'anchor'
];

module.exports = function parseuri(str) {
    var src = str,
        b = str.indexOf('['),
        e = str.indexOf(']');

    if (b != -1 && e != -1) {
        str = str.substring(0, b) + str.substring(b, e).replace(/:/g, ';') + str.substring(e, str.length);
    }

    var m = re.exec(str || ''),
        uri = {},
        i = 14;

    while (i--) {
        uri[parts[i]] = m[i] || '';
    }

    if (b != -1 && e != -1) {
        uri.source = src;
        uri.host = uri.host.substring(1, uri.host.length - 1).replace(/;/g, ':');
        uri.authority = uri.authority.replace('[', '').replace(']', '').replace(/;/g, ':');
        uri.ipv6uri = true;
    }

    return uri;
};

},{}],40:[function(require,module,exports){
// shim for using process in browser
var process = module.exports = {};

// cached from whatever global is present so that test runners that stub it
// don't break things.  But we need to wrap it in a try catch in case it is
// wrapped in strict mode code which doesn't define any globals.  It's inside a
// function because try/catches deoptimize in certain engines.

var cachedSetTimeout;
var cachedClearTimeout;

function defaultSetTimout() {
    throw new Error('setTimeout has not been defined');
}
function defaultClearTimeout () {
    throw new Error('clearTimeout has not been defined');
}
(function () {
    try {
        if (typeof setTimeout === 'function') {
            cachedSetTimeout = setTimeout;
        } else {
            cachedSetTimeout = defaultSetTimout;
        }
    } catch (e) {
        cachedSetTimeout = defaultSetTimout;
    }
    try {
        if (typeof clearTimeout === 'function') {
            cachedClearTimeout = clearTimeout;
        } else {
            cachedClearTimeout = defaultClearTimeout;
        }
    } catch (e) {
        cachedClearTimeout = defaultClearTimeout;
    }
} ())
function runTimeout(fun) {
    if (cachedSetTimeout === setTimeout) {
        //normal enviroments in sane situations
        return setTimeout(fun, 0);
    }
    // if setTimeout wasn't available but was latter defined
    if ((cachedSetTimeout === defaultSetTimout || !cachedSetTimeout) && setTimeout) {
        cachedSetTimeout = setTimeout;
        return setTimeout(fun, 0);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedSetTimeout(fun, 0);
    } catch(e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
            return cachedSetTimeout.call(null, fun, 0);
        } catch(e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error
            return cachedSetTimeout.call(this, fun, 0);
        }
    }


}
function runClearTimeout(marker) {
    if (cachedClearTimeout === clearTimeout) {
        //normal enviroments in sane situations
        return clearTimeout(marker);
    }
    // if clearTimeout wasn't available but was latter defined
    if ((cachedClearTimeout === defaultClearTimeout || !cachedClearTimeout) && clearTimeout) {
        cachedClearTimeout = clearTimeout;
        return clearTimeout(marker);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedClearTimeout(marker);
    } catch (e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't  trust the global object when called normally
            return cachedClearTimeout.call(null, marker);
        } catch (e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error.
            // Some versions of I.E. have different rules for clearTimeout vs setTimeout
            return cachedClearTimeout.call(this, marker);
        }
    }



}
var queue = [];
var draining = false;
var currentQueue;
var queueIndex = -1;

function cleanUpNextTick() {
    if (!draining || !currentQueue) {
        return;
    }
    draining = false;
    if (currentQueue.length) {
        queue = currentQueue.concat(queue);
    } else {
        queueIndex = -1;
    }
    if (queue.length) {
        drainQueue();
    }
}

function drainQueue() {
    if (draining) {
        return;
    }
    var timeout = runTimeout(cleanUpNextTick);
    draining = true;

    var len = queue.length;
    while(len) {
        currentQueue = queue;
        queue = [];
        while (++queueIndex < len) {
            if (currentQueue) {
                currentQueue[queueIndex].run();
            }
        }
        queueIndex = -1;
        len = queue.length;
    }
    currentQueue = null;
    draining = false;
    runClearTimeout(timeout);
}

process.nextTick = function (fun) {
    var args = new Array(arguments.length - 1);
    if (arguments.length > 1) {
        for (var i = 1; i < arguments.length; i++) {
            args[i - 1] = arguments[i];
        }
    }
    queue.push(new Item(fun, args));
    if (queue.length === 1 && !draining) {
        runTimeout(drainQueue);
    }
};

// v8 likes predictible objects
function Item(fun, array) {
    this.fun = fun;
    this.array = array;
}
Item.prototype.run = function () {
    this.fun.apply(null, this.array);
};
process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];
process.version = ''; // empty string to avoid regexp issues
process.versions = {};

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;
process.prependListener = noop;
process.prependOnceListener = noop;

process.listeners = function (name) { return [] }

process.binding = function (name) {
    throw new Error('process.binding is not supported');
};

process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};
process.umask = function() { return 0; };

},{}],41:[function(require,module,exports){
/*! queue-microtask. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
let promise

module.exports = typeof queueMicrotask === 'function'
  ? queueMicrotask
  // reuse resolved promise, and allocate it lazily
  : cb => (promise || (promise = Promise.resolve()))
    .then(cb)
    .catch(err => setTimeout(() => { throw err }, 0))

},{}],42:[function(require,module,exports){
(function (process,global){(function (){
'use strict'

// limit of Crypto.getRandomValues()
// https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
var MAX_BYTES = 65536

// Node supports requesting up to this number of bytes
// https://github.com/nodejs/node/blob/master/lib/internal/crypto/random.js#L48
var MAX_UINT32 = 4294967295

function oldBrowser () {
  throw new Error('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11')
}

var Buffer = require('safe-buffer').Buffer
var crypto = global.crypto || global.msCrypto

if (crypto && crypto.getRandomValues) {
  module.exports = randomBytes
} else {
  module.exports = oldBrowser
}

function randomBytes (size, cb) {
  // phantomjs needs to throw
  if (size > MAX_UINT32) throw new RangeError('requested too many random bytes')

  var bytes = Buffer.allocUnsafe(size)

  if (size > 0) {  // getRandomValues fails on IE if size == 0
    if (size > MAX_BYTES) { // this is the max bytes crypto.getRandomValues
      // can do at once see https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
      for (var generated = 0; generated < size; generated += MAX_BYTES) {
        // buffer.slice automatically checks if the end is past the end of
        // the buffer so we don't have to here
        crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES))
      }
    } else {
      crypto.getRandomValues(bytes)
    }
  }

  if (typeof cb === 'function') {
    return process.nextTick(function () {
      cb(null, bytes)
    })
  }

  return bytes
}

}).call(this)}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"_process":40,"safe-buffer":58}],43:[function(require,module,exports){
'use strict';

function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; subClass.__proto__ = superClass; }

var codes = {};

function createErrorType(code, message, Base) {
  if (!Base) {
    Base = Error;
  }

  function getMessage(arg1, arg2, arg3) {
    if (typeof message === 'string') {
      return message;
    } else {
      return message(arg1, arg2, arg3);
    }
  }

  var NodeError =
  /*#__PURE__*/
  function (_Base) {
    _inheritsLoose(NodeError, _Base);

    function NodeError(arg1, arg2, arg3) {
      return _Base.call(this, getMessage(arg1, arg2, arg3)) || this;
    }

    return NodeError;
  }(Base);

  NodeError.prototype.name = Base.name;
  NodeError.prototype.code = code;
  codes[code] = NodeError;
} // https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js


function oneOf(expected, thing) {
  if (Array.isArray(expected)) {
    var len = expected.length;
    expected = expected.map(function (i) {
      return String(i);
    });

    if (len > 2) {
      return "one of ".concat(thing, " ").concat(expected.slice(0, len - 1).join(', '), ", or ") + expected[len - 1];
    } else if (len === 2) {
      return "one of ".concat(thing, " ").concat(expected[0], " or ").concat(expected[1]);
    } else {
      return "of ".concat(thing, " ").concat(expected[0]);
    }
  } else {
    return "of ".concat(thing, " ").concat(String(expected));
  }
} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith


function startsWith(str, search, pos) {
  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith


function endsWith(str, search, this_len) {
  if (this_len === undefined || this_len > str.length) {
    this_len = str.length;
  }

  return str.substring(this_len - search.length, this_len) === search;
} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes


function includes(str, search, start) {
  if (typeof start !== 'number') {
    start = 0;
  }

  if (start + search.length > str.length) {
    return false;
  } else {
    return str.indexOf(search, start) !== -1;
  }
}

createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
  return 'The value "' + value + '" is invalid for option "' + name + '"';
}, TypeError);
createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
  // determiner: 'must be' or 'must not be'
  var determiner;

  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
    determiner = 'must not be';
    expected = expected.replace(/^not /, '');
  } else {
    determiner = 'must be';
  }

  var msg;

  if (endsWith(name, ' argument')) {
    // For cases like 'first argument'
    msg = "The ".concat(name, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
  } else {
    var type = includes(name, '.') ? 'property' : 'argument';
    msg = "The \"".concat(name, "\" ").concat(type, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
  }

  msg += ". Received type ".concat(typeof actual);
  return msg;
}, TypeError);
createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
  return 'The ' + name + ' method is not implemented';
});
createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
createErrorType('ERR_STREAM_DESTROYED', function (name) {
  return 'Cannot call ' + name + ' after a stream was destroyed';
});
createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
  return 'Unknown encoding: ' + arg;
}, TypeError);
createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
module.exports.codes = codes;

},{}],44:[function(require,module,exports){
(function (process){(function (){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// a duplex stream is just a stream that is both readable and writable.
// Since JS doesn't have multiple prototypal inheritance, this class
// prototypally inherits from Readable, and then parasitically from
// Writable.
'use strict';
/*<replacement>*/

var objectKeys = Object.keys || function (obj) {
  var keys = [];

  for (var key in obj) {
    keys.push(key);
  }

  return keys;
};
/*</replacement>*/


module.exports = Duplex;

var Readable = require('./_stream_readable');

var Writable = require('./_stream_writable');

require('inherits')(Duplex, Readable);

{
  // Allow the keys array to be GC'ed.
  var keys = objectKeys(Writable.prototype);

  for (var v = 0; v < keys.length; v++) {
    var method = keys[v];
    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
  }
}

function Duplex(options) {
  if (!(this instanceof Duplex)) return new Duplex(options);
  Readable.call(this, options);
  Writable.call(this, options);
  this.allowHalfOpen = true;

  if (options) {
    if (options.readable === false) this.readable = false;
    if (options.writable === false) this.writable = false;

    if (options.allowHalfOpen === false) {
      this.allowHalfOpen = false;
      this.once('end', onend);
    }
  }
}

Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState.highWaterMark;
  }
});
Object.defineProperty(Duplex.prototype, 'writableBuffer', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState && this._writableState.getBuffer();
  }
});
Object.defineProperty(Duplex.prototype, 'writableLength', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState.length;
  }
}); // the no-half-open enforcer

function onend() {
  // If the writable side ended, then we're ok.
  if (this._writableState.ended) return; // no more data can be written.
  // But allow more writes to happen in this tick.

  process.nextTick(onEndNT, this);
}

function onEndNT(self) {
  self.end();
}

Object.defineProperty(Duplex.prototype, 'destroyed', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    if (this._readableState === undefined || this._writableState === undefined) {
      return false;
    }

    return this._readableState.destroyed && this._writableState.destroyed;
  },
  set: function set(value) {
    // we ignore the value if the stream
    // has not been initialized yet
    if (this._readableState === undefined || this._writableState === undefined) {
      return;
    } // backward compatibility, the user is explicitly
    // managing destroyed


    this._readableState.destroyed = value;
    this._writableState.destroyed = value;
  }
});
}).call(this)}).call(this,require('_process'))
},{"./_stream_readable":46,"./_stream_writable":48,"_process":40,"inherits":36}],45:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// a passthrough stream.
// basically just the most minimal sort of Transform stream.
// Every written chunk gets output as-is.
'use strict';

module.exports = PassThrough;

var Transform = require('./_stream_transform');

require('inherits')(PassThrough, Transform);

function PassThrough(options) {
  if (!(this instanceof PassThrough)) return new PassThrough(options);
  Transform.call(this, options);
}

PassThrough.prototype._transform = function (chunk, encoding, cb) {
  cb(null, chunk);
};
},{"./_stream_transform":47,"inherits":36}],46:[function(require,module,exports){
(function (process,global){(function (){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';

module.exports = Readable;
/*<replacement>*/

var Duplex;
/*</replacement>*/

Readable.ReadableState = ReadableState;
/*<replacement>*/

var EE = require('events').EventEmitter;

var EElistenerCount = function EElistenerCount(emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

/*<replacement>*/


var Stream = require('./internal/streams/stream');
/*</replacement>*/


var Buffer = require('buffer').Buffer;

var OurUint8Array = global.Uint8Array || function () {};

function _uint8ArrayToBuffer(chunk) {
  return Buffer.from(chunk);
}

function _isUint8Array(obj) {
  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
}
/*<replacement>*/


var debugUtil = require('util');

var debug;

if (debugUtil && debugUtil.debuglog) {
  debug = debugUtil.debuglog('stream');
} else {
  debug = function debug() {};
}
/*</replacement>*/


var BufferList = require('./internal/streams/buffer_list');

var destroyImpl = require('./internal/streams/destroy');

var _require = require('./internal/streams/state'),
    getHighWaterMark = _require.getHighWaterMark;

var _require$codes = require('../errors').codes,
    ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
    ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
    ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
    ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT; // Lazy loaded to improve the startup performance.


var StringDecoder;
var createReadableStreamAsyncIterator;
var from;

require('inherits')(Readable, Stream);

var errorOrDestroy = destroyImpl.errorOrDestroy;
var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];

function prependListener(emitter, event, fn) {
  // Sadly this is not cacheable as some libraries bundle their own
  // event emitter implementation with them.
  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn); // This is a hack to make sure that our error handler is attached before any
  // userland ones.  NEVER DO THIS. This is here only because this code needs
  // to continue to work with older versions of Node.js that do not include
  // the prependListener() method. The goal is to eventually remove this hack.

  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
}

function ReadableState(options, stream, isDuplex) {
  Duplex = Duplex || require('./_stream_duplex');
  options = options || {}; // Duplex streams are both readable and writable, but share
  // the same options object.
  // However, some cases require setting options to different
  // values for the readable and the writable sides of the duplex stream.
  // These options can be provided separately as readableXXX and writableXXX.

  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away

  this.objectMode = !!options.objectMode;
  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode; // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"

  this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex); // A linked list is used to store data chunks instead of an array because the
  // linked list can remove elements from the beginning faster than
  // array.shift()

  this.buffer = new BufferList();
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false; // a flag to be able to tell if the event 'readable'/'data' is emitted
  // immediately, or on a later tick.  We set this to true at first, because
  // any actions that shouldn't happen until "later" should generally also
  // not happen before the first read call.

  this.sync = true; // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.

  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;
  this.resumeScheduled = false;
  this.paused = true; // Should close be emitted on destroy. Defaults to true.

  this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'end' (and potentially 'finish')

  this.autoDestroy = !!options.autoDestroy; // has it been destroyed

  this.destroyed = false; // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.

  this.defaultEncoding = options.defaultEncoding || 'utf8'; // the number of writers that are awaiting a drain event in .pipe()s

  this.awaitDrain = 0; // if true, a maybeReadMore has been scheduled

  this.readingMore = false;
  this.decoder = null;
  this.encoding = null;

  if (options.encoding) {
    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

function Readable(options) {
  Duplex = Duplex || require('./_stream_duplex');
  if (!(this instanceof Readable)) return new Readable(options); // Checking for a Stream.Duplex instance is faster here instead of inside
  // the ReadableState constructor, at least with V8 6.5

  var isDuplex = this instanceof Duplex;
  this._readableState = new ReadableState(options, this, isDuplex); // legacy

  this.readable = true;

  if (options) {
    if (typeof options.read === 'function') this._read = options.read;
    if (typeof options.destroy === 'function') this._destroy = options.destroy;
  }

  Stream.call(this);
}

Object.defineProperty(Readable.prototype, 'destroyed', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    if (this._readableState === undefined) {
      return false;
    }

    return this._readableState.destroyed;
  },
  set: function set(value) {
    // we ignore the value if the stream
    // has not been initialized yet
    if (!this._readableState) {
      return;
    } // backward compatibility, the user is explicitly
    // managing destroyed


    this._readableState.destroyed = value;
  }
});
Readable.prototype.destroy = destroyImpl.destroy;
Readable.prototype._undestroy = destroyImpl.undestroy;

Readable.prototype._destroy = function (err, cb) {
  cb(err);
}; // Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.


Readable.prototype.push = function (chunk, encoding) {
  var state = this._readableState;
  var skipChunkCheck;

  if (!state.objectMode) {
    if (typeof chunk === 'string') {
      encoding = encoding || state.defaultEncoding;

      if (encoding !== state.encoding) {
        chunk = Buffer.from(chunk, encoding);
        encoding = '';
      }

      skipChunkCheck = true;
    }
  } else {
    skipChunkCheck = true;
  }

  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
}; // Unshift should *always* be something directly out of read()


Readable.prototype.unshift = function (chunk) {
  return readableAddChunk(this, chunk, null, true, false);
};

function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
  debug('readableAddChunk', chunk);
  var state = stream._readableState;

  if (chunk === null) {
    state.reading = false;
    onEofChunk(stream, state);
  } else {
    var er;
    if (!skipChunkCheck) er = chunkInvalid(state, chunk);

    if (er) {
      errorOrDestroy(stream, er);
    } else if (state.objectMode || chunk && chunk.length > 0) {
      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
        chunk = _uint8ArrayToBuffer(chunk);
      }

      if (addToFront) {
        if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
      } else if (state.ended) {
        errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
      } else if (state.destroyed) {
        return false;
      } else {
        state.reading = false;

        if (state.decoder && !encoding) {
          chunk = state.decoder.write(chunk);
          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
        } else {
          addChunk(stream, state, chunk, false);
        }
      }
    } else if (!addToFront) {
      state.reading = false;
      maybeReadMore(stream, state);
    }
  } // We can push more data if we are below the highWaterMark.
  // Also, if we have no data yet, we can stand some more bytes.
  // This is to work around cases where hwm=0, such as the repl.


  return !state.ended && (state.length < state.highWaterMark || state.length === 0);
}

function addChunk(stream, state, chunk, addToFront) {
  if (state.flowing && state.length === 0 && !state.sync) {
    state.awaitDrain = 0;
    stream.emit('data', chunk);
  } else {
    // update the buffer info.
    state.length += state.objectMode ? 1 : chunk.length;
    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
    if (state.needReadable) emitReadable(stream);
  }

  maybeReadMore(stream, state);
}

function chunkInvalid(state, chunk) {
  var er;

  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
  }

  return er;
}

Readable.prototype.isPaused = function () {
  return this._readableState.flowing === false;
}; // backwards compatibility.


Readable.prototype.setEncoding = function (enc) {
  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
  var decoder = new StringDecoder(enc);
  this._readableState.decoder = decoder; // If setEncoding(null), decoder.encoding equals utf8

  this._readableState.encoding = this._readableState.decoder.encoding; // Iterate over current buffer to convert already stored Buffers:

  var p = this._readableState.buffer.head;
  var content = '';

  while (p !== null) {
    content += decoder.write(p.data);
    p = p.next;
  }

  this._readableState.buffer.clear();

  if (content !== '') this._readableState.buffer.push(content);
  this._readableState.length = content.length;
  return this;
}; // Don't raise the hwm > 1GB


var MAX_HWM = 0x40000000;

function computeNewHighWaterMark(n) {
  if (n >= MAX_HWM) {
    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2 to prevent increasing hwm excessively in
    // tiny amounts
    n--;
    n |= n >>> 1;
    n |= n >>> 2;
    n |= n >>> 4;
    n |= n >>> 8;
    n |= n >>> 16;
    n++;
  }

  return n;
} // This function is designed to be inlinable, so please take care when making
// changes to the function body.


function howMuchToRead(n, state) {
  if (n <= 0 || state.length === 0 && state.ended) return 0;
  if (state.objectMode) return 1;

  if (n !== n) {
    // Only flow one buffer at a time
    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
  } // If we're asking for more than the current hwm, then raise the hwm.


  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
  if (n <= state.length) return n; // Don't have enough

  if (!state.ended) {
    state.needReadable = true;
    return 0;
  }

  return state.length;
} // you can override either this method, or the async _read(n) below.


Readable.prototype.read = function (n) {
  debug('read', n);
  n = parseInt(n, 10);
  var state = this._readableState;
  var nOrig = n;
  if (n !== 0) state.emittedReadable = false; // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.

  if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state); // if we've ended, and we're now clear, then finish it up.

  if (n === 0 && state.ended) {
    if (state.length === 0) endReadable(this);
    return null;
  } // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.
  // if we need a readable event, then we need to do some reading.


  var doRead = state.needReadable;
  debug('need readable', doRead); // if we currently have less than the highWaterMark, then also read some

  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  } // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.


  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  } else if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true; // if the length is currently zero, then we *need* a readable event.

    if (state.length === 0) state.needReadable = true; // call internal read method

    this._read(state.highWaterMark);

    state.sync = false; // If _read pushed data synchronously, then `reading` will be false,
    // and we need to re-evaluate how much data we can return to the user.

    if (!state.reading) n = howMuchToRead(nOrig, state);
  }

  var ret;
  if (n > 0) ret = fromList(n, state);else ret = null;

  if (ret === null) {
    state.needReadable = state.length <= state.highWaterMark;
    n = 0;
  } else {
    state.length -= n;
    state.awaitDrain = 0;
  }

  if (state.length === 0) {
    // If we have nothing in the buffer, then we want to know
    // as soon as we *do* get something into the buffer.
    if (!state.ended) state.needReadable = true; // If we tried to read() past the EOF, then emit end on the next tick.

    if (nOrig !== n && state.ended) endReadable(this);
  }

  if (ret !== null) this.emit('data', ret);
  return ret;
};

function onEofChunk(stream, state) {
  debug('onEofChunk');
  if (state.ended) return;

  if (state.decoder) {
    var chunk = state.decoder.end();

    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }

  state.ended = true;

  if (state.sync) {
    // if we are sync, wait until next tick to emit the data.
    // Otherwise we risk emitting data in the flow()
    // the readable code triggers during a read() call
    emitReadable(stream);
  } else {
    // emit 'readable' now to make sure it gets picked up.
    state.needReadable = false;

    if (!state.emittedReadable) {
      state.emittedReadable = true;
      emitReadable_(stream);
    }
  }
} // Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.


function emitReadable(stream) {
  var state = stream._readableState;
  debug('emitReadable', state.needReadable, state.emittedReadable);
  state.needReadable = false;

  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    process.nextTick(emitReadable_, stream);
  }
}

function emitReadable_(stream) {
  var state = stream._readableState;
  debug('emitReadable_', state.destroyed, state.length, state.ended);

  if (!state.destroyed && (state.length || state.ended)) {
    stream.emit('readable');
    state.emittedReadable = false;
  } // The stream needs another readable event if
  // 1. It is not flowing, as the flow mechanism will take
  //    care of it.
  // 2. It is not ended.
  // 3. It is below the highWaterMark, so we can schedule
  //    another readable later.


  state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
  flow(stream);
} // at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.


function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    process.nextTick(maybeReadMore_, stream, state);
  }
}

function maybeReadMore_(stream, state) {
  // Attempt to read more data if we should.
  //
  // The conditions for reading more data are (one of):
  // - Not enough data buffered (state.length < state.highWaterMark). The loop
  //   is responsible for filling the buffer with enough data if such data
  //   is available. If highWaterMark is 0 and we are not in the flowing mode
  //   we should _not_ attempt to buffer any extra data. We'll get more data
  //   when the stream consumer calls read() instead.
  // - No data in the buffer, and the stream is in flowing mode. In this mode
  //   the loop below is responsible for ensuring read() is called. Failing to
  //   call read here would abort the flow and there's no other mechanism for
  //   continuing the flow if the stream consumer has just subscribed to the
  //   'data' event.
  //
  // In addition to the above conditions to keep reading data, the following
  // conditions prevent the data from being read:
  // - The stream has ended (state.ended).
  // - There is already a pending 'read' operation (state.reading). This is a
  //   case where the the stream has called the implementation defined _read()
  //   method, but they are processing the call asynchronously and have _not_
  //   called push() with new data. In this case we skip performing more
  //   read()s. The execution ends in this method again after the _read() ends
  //   up calling push() with more data.
  while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
    var len = state.length;
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length) // didn't get any data, stop spinning.
      break;
  }

  state.readingMore = false;
} // abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.


Readable.prototype._read = function (n) {
  errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
};

Readable.prototype.pipe = function (dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;

    case 1:
      state.pipes = [state.pipes, dest];
      break;

    default:
      state.pipes.push(dest);
      break;
  }

  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
  var endFn = doEnd ? onend : unpipe;
  if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
  dest.on('unpipe', onunpipe);

  function onunpipe(readable, unpipeInfo) {
    debug('onunpipe');

    if (readable === src) {
      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
        unpipeInfo.hasUnpiped = true;
        cleanup();
      }
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  } // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.


  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);
  var cleanedUp = false;

  function cleanup() {
    debug('cleanup'); // cleanup event handlers once the pipe is broken

    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', unpipe);
    src.removeListener('data', ondata);
    cleanedUp = true; // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.

    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
  }

  src.on('data', ondata);

  function ondata(chunk) {
    debug('ondata');
    var ret = dest.write(chunk);
    debug('dest.write', ret);

    if (ret === false) {
      // If the user unpiped during `dest.write()`, it is possible
      // to get stuck in a permanently paused state if that write
      // also returned false.
      // => Check whether `dest` is still a piping destination.
      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
        debug('false write response, pause', state.awaitDrain);
        state.awaitDrain++;
      }

      src.pause();
    }
  } // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.


  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
  } // Make sure our error handler is attached before userland ones.


  prependListener(dest, 'error', onerror); // Both close and finish should trigger unpipe, but only once.

  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }

  dest.once('close', onclose);

  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }

  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  } // tell the dest that it's being piped to


  dest.emit('pipe', src); // start the flow if it hasn't been started already.

  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function pipeOnDrainFunctionResult() {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain) state.awaitDrain--;

    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
      state.flowing = true;
      flow(src);
    }
  };
}

Readable.prototype.unpipe = function (dest) {
  var state = this._readableState;
  var unpipeInfo = {
    hasUnpiped: false
  }; // if we're not piping anywhere, then do nothing.

  if (state.pipesCount === 0) return this; // just one destination.  most common case.

  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes) return this;
    if (!dest) dest = state.pipes; // got a match.

    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest) dest.emit('unpipe', this, unpipeInfo);
    return this;
  } // slow case. multiple pipe destinations.


  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var i = 0; i < len; i++) {
      dests[i].emit('unpipe', this, {
        hasUnpiped: false
      });
    }

    return this;
  } // try to find the right one.


  var index = indexOf(state.pipes, dest);
  if (index === -1) return this;
  state.pipes.splice(index, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1) state.pipes = state.pipes[0];
  dest.emit('unpipe', this, unpipeInfo);
  return this;
}; // set up data events if they are asked for
// Ensure readable listeners eventually get something


Readable.prototype.on = function (ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);
  var state = this._readableState;

  if (ev === 'data') {
    // update readableListening so that resume() may be a no-op
    // a few lines down. This is needed to support once('readable').
    state.readableListening = this.listenerCount('readable') > 0; // Try start flowing on next tick if stream isn't explicitly paused

    if (state.flowing !== false) this.resume();
  } else if (ev === 'readable') {
    if (!state.endEmitted && !state.readableListening) {
      state.readableListening = state.needReadable = true;
      state.flowing = false;
      state.emittedReadable = false;
      debug('on readable', state.length, state.reading);

      if (state.length) {
        emitReadable(this);
      } else if (!state.reading) {
        process.nextTick(nReadingNextTick, this);
      }
    }
  }

  return res;
};

Readable.prototype.addListener = Readable.prototype.on;

Readable.prototype.removeListener = function (ev, fn) {
  var res = Stream.prototype.removeListener.call(this, ev, fn);

  if (ev === 'readable') {
    // We need to check if there is someone still listening to
    // readable and reset the state. However this needs to happen
    // after readable has been emitted but before I/O (nextTick) to
    // support once('readable', fn) cycles. This means that calling
    // resume within the same tick will have no
    // effect.
    process.nextTick(updateReadableListening, this);
  }

  return res;
};

Readable.prototype.removeAllListeners = function (ev) {
  var res = Stream.prototype.removeAllListeners.apply(this, arguments);

  if (ev === 'readable' || ev === undefined) {
    // We need to check if there is someone still listening to
    // readable and reset the state. However this needs to happen
    // after readable has been emitted but before I/O (nextTick) to
    // support once('readable', fn) cycles. This means that calling
    // resume within the same tick will have no
    // effect.
    process.nextTick(updateReadableListening, this);
  }

  return res;
};

function updateReadableListening(self) {
  var state = self._readableState;
  state.readableListening = self.listenerCount('readable') > 0;

  if (state.resumeScheduled && !state.paused) {
    // flowing needs to be set to true now, otherwise
    // the upcoming resume will not flow.
    state.flowing = true; // crude way to check if we should resume
  } else if (self.listenerCount('data') > 0) {
    self.resume();
  }
}

function nReadingNextTick(self) {
  debug('readable nexttick read 0');
  self.read(0);
} // pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.


Readable.prototype.resume = function () {
  var state = this._readableState;

  if (!state.flowing) {
    debug('resume'); // we flow only if there is no one listening
    // for readable, but we still have to call
    // resume()

    state.flowing = !state.readableListening;
    resume(this, state);
  }

  state.paused = false;
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    process.nextTick(resume_, stream, state);
  }
}

function resume_(stream, state) {
  debug('resume', state.reading);

  if (!state.reading) {
    stream.read(0);
  }

  state.resumeScheduled = false;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading) stream.read(0);
}

Readable.prototype.pause = function () {
  debug('call pause flowing=%j', this._readableState.flowing);

  if (this._readableState.flowing !== false) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }

  this._readableState.paused = true;
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);

  while (state.flowing && stream.read() !== null) {
    ;
  }
} // wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.


Readable.prototype.wrap = function (stream) {
  var _this = this;

  var state = this._readableState;
  var paused = false;
  stream.on('end', function () {
    debug('wrapped end');

    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length) _this.push(chunk);
    }

    _this.push(null);
  });
  stream.on('data', function (chunk) {
    debug('wrapped data');
    if (state.decoder) chunk = state.decoder.write(chunk); // don't skip over falsy values in objectMode

    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;

    var ret = _this.push(chunk);

    if (!ret) {
      paused = true;
      stream.pause();
    }
  }); // proxy all the other methods.
  // important when wrapping filters and duplexes.

  for (var i in stream) {
    if (this[i] === undefined && typeof stream[i] === 'function') {
      this[i] = function methodWrap(method) {
        return function methodWrapReturnFunction() {
          return stream[method].apply(stream, arguments);
        };
      }(i);
    }
  } // proxy certain important events.


  for (var n = 0; n < kProxyEvents.length; n++) {
    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
  } // when we try to consume some more bytes, simply unpause the
  // underlying stream.


  this._read = function (n) {
    debug('wrapped _read', n);

    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return this;
};

if (typeof Symbol === 'function') {
  Readable.prototype[Symbol.asyncIterator] = function () {
    if (createReadableStreamAsyncIterator === undefined) {
      createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
    }

    return createReadableStreamAsyncIterator(this);
  };
}

Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._readableState.highWaterMark;
  }
});
Object.defineProperty(Readable.prototype, 'readableBuffer', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._readableState && this._readableState.buffer;
  }
});
Object.defineProperty(Readable.prototype, 'readableFlowing', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._readableState.flowing;
  },
  set: function set(state) {
    if (this._readableState) {
      this._readableState.flowing = state;
    }
  }
}); // exposed for testing purposes only.

Readable._fromList = fromList;
Object.defineProperty(Readable.prototype, 'readableLength', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._readableState.length;
  }
}); // Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.

function fromList(n, state) {
  // nothing buffered
  if (state.length === 0) return null;
  var ret;
  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
    // read it all, truncate the list
    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
    state.buffer.clear();
  } else {
    // read part of list
    ret = state.buffer.consume(n, state.decoder);
  }
  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;
  debug('endReadable', state.endEmitted);

  if (!state.endEmitted) {
    state.ended = true;
    process.nextTick(endReadableNT, state, stream);
  }
}

function endReadableNT(state, stream) {
  debug('endReadableNT', state.endEmitted, state.length); // Check that we didn't get one last unshift.

  if (!state.endEmitted && state.length === 0) {
    state.endEmitted = true;
    stream.readable = false;
    stream.emit('end');

    if (state.autoDestroy) {
      // In case of duplex streams we need a way to detect
      // if the writable side is ready for autoDestroy as well
      var wState = stream._writableState;

      if (!wState || wState.autoDestroy && wState.finished) {
        stream.destroy();
      }
    }
  }
}

if (typeof Symbol === 'function') {
  Readable.from = function (iterable, opts) {
    if (from === undefined) {
      from = require('./internal/streams/from');
    }

    return from(Readable, iterable, opts);
  };
}

function indexOf(xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }

  return -1;
}
}).call(this)}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../errors":43,"./_stream_duplex":44,"./internal/streams/async_iterator":49,"./internal/streams/buffer_list":50,"./internal/streams/destroy":51,"./internal/streams/from":53,"./internal/streams/state":55,"./internal/streams/stream":56,"_process":40,"buffer":9,"events":30,"inherits":36,"string_decoder/":77,"util":8}],47:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.
'use strict';

module.exports = Transform;

var _require$codes = require('../errors').codes,
    ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
    ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
    ERR_TRANSFORM_ALREADY_TRANSFORMING = _require$codes.ERR_TRANSFORM_ALREADY_TRANSFORMING,
    ERR_TRANSFORM_WITH_LENGTH_0 = _require$codes.ERR_TRANSFORM_WITH_LENGTH_0;

var Duplex = require('./_stream_duplex');

require('inherits')(Transform, Duplex);

function afterTransform(er, data) {
  var ts = this._transformState;
  ts.transforming = false;
  var cb = ts.writecb;

  if (cb === null) {
    return this.emit('error', new ERR_MULTIPLE_CALLBACK());
  }

  ts.writechunk = null;
  ts.writecb = null;
  if (data != null) // single equals check for both `null` and `undefined`
    this.push(data);
  cb(er);
  var rs = this._readableState;
  rs.reading = false;

  if (rs.needReadable || rs.length < rs.highWaterMark) {
    this._read(rs.highWaterMark);
  }
}

function Transform(options) {
  if (!(this instanceof Transform)) return new Transform(options);
  Duplex.call(this, options);
  this._transformState = {
    afterTransform: afterTransform.bind(this),
    needTransform: false,
    transforming: false,
    writecb: null,
    writechunk: null,
    writeencoding: null
  }; // start out asking for a readable event once data is transformed.

  this._readableState.needReadable = true; // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.

  this._readableState.sync = false;

  if (options) {
    if (typeof options.transform === 'function') this._transform = options.transform;
    if (typeof options.flush === 'function') this._flush = options.flush;
  } // When the writable side finishes, then flush out anything remaining.


  this.on('prefinish', prefinish);
}

function prefinish() {
  var _this = this;

  if (typeof this._flush === 'function' && !this._readableState.destroyed) {
    this._flush(function (er, data) {
      done(_this, er, data);
    });
  } else {
    done(this, null, null);
  }
}

Transform.prototype.push = function (chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
}; // This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.


Transform.prototype._transform = function (chunk, encoding, cb) {
  cb(new ERR_METHOD_NOT_IMPLEMENTED('_transform()'));
};

Transform.prototype._write = function (chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;

  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
  }
}; // Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.


Transform.prototype._read = function (n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && !ts.transforming) {
    ts.transforming = true;

    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};

Transform.prototype._destroy = function (err, cb) {
  Duplex.prototype._destroy.call(this, err, function (err2) {
    cb(err2);
  });
};

function done(stream, er, data) {
  if (er) return stream.emit('error', er);
  if (data != null) // single equals check for both `null` and `undefined`
    stream.push(data); // TODO(BridgeAR): Write a test for these two error cases
  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided

  if (stream._writableState.length) throw new ERR_TRANSFORM_WITH_LENGTH_0();
  if (stream._transformState.transforming) throw new ERR_TRANSFORM_ALREADY_TRANSFORMING();
  return stream.push(null);
}
},{"../errors":43,"./_stream_duplex":44,"inherits":36}],48:[function(require,module,exports){
(function (process,global){(function (){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// A bit simpler than readable streams.
// Implement an async ._write(chunk, encoding, cb), and it'll handle all
// the drain event emission and buffering.
'use strict';

module.exports = Writable;
/* <replacement> */

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
  this.next = null;
} // It seems a linked list but it is not
// there will be only 2 of these for each stream


function CorkedRequest(state) {
  var _this = this;

  this.next = null;
  this.entry = null;

  this.finish = function () {
    onCorkedFinish(_this, state);
  };
}
/* </replacement> */

/*<replacement>*/


var Duplex;
/*</replacement>*/

Writable.WritableState = WritableState;
/*<replacement>*/

var internalUtil = {
  deprecate: require('util-deprecate')
};
/*</replacement>*/

/*<replacement>*/

var Stream = require('./internal/streams/stream');
/*</replacement>*/


var Buffer = require('buffer').Buffer;

var OurUint8Array = global.Uint8Array || function () {};

function _uint8ArrayToBuffer(chunk) {
  return Buffer.from(chunk);
}

function _isUint8Array(obj) {
  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
}

var destroyImpl = require('./internal/streams/destroy');

var _require = require('./internal/streams/state'),
    getHighWaterMark = _require.getHighWaterMark;

var _require$codes = require('../errors').codes,
    ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
    ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
    ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
    ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
    ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
    ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
    ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
    ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;

var errorOrDestroy = destroyImpl.errorOrDestroy;

require('inherits')(Writable, Stream);

function nop() {}

function WritableState(options, stream, isDuplex) {
  Duplex = Duplex || require('./_stream_duplex');
  options = options || {}; // Duplex streams are both readable and writable, but share
  // the same options object.
  // However, some cases require setting options to different
  // values for the readable and the writable sides of the duplex stream,
  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.

  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag to indicate whether or not this stream
  // contains buffers or objects.

  this.objectMode = !!options.objectMode;
  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode; // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()

  this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex); // if _final has been called

  this.finalCalled = false; // drain event flag.

  this.needDrain = false; // at the start of calling end()

  this.ending = false; // when end() has been called, and returned

  this.ended = false; // when 'finish' is emitted

  this.finished = false; // has it been destroyed

  this.destroyed = false; // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.

  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode; // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.

  this.defaultEncoding = options.defaultEncoding || 'utf8'; // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.

  this.length = 0; // a flag to see when we're in the middle of a write.

  this.writing = false; // when true all writes will be buffered until .uncork() call

  this.corked = 0; // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.

  this.sync = true; // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.

  this.bufferProcessing = false; // the callback that's passed to _write(chunk,cb)

  this.onwrite = function (er) {
    onwrite(stream, er);
  }; // the callback that the user supplies to write(chunk,encoding,cb)


  this.writecb = null; // the amount that is being written when _write is called.

  this.writelen = 0;
  this.bufferedRequest = null;
  this.lastBufferedRequest = null; // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted

  this.pendingcb = 0; // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams

  this.prefinished = false; // True if the error was already emitted and should not be thrown again

  this.errorEmitted = false; // Should close be emitted on destroy. Defaults to true.

  this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'finish' (and potentially 'end')

  this.autoDestroy = !!options.autoDestroy; // count buffered requests

  this.bufferedRequestCount = 0; // allocate the first CorkedRequest, there is always
  // one allocated and free to use, and we maintain at most two

  this.corkedRequestsFree = new CorkedRequest(this);
}

WritableState.prototype.getBuffer = function getBuffer() {
  var current = this.bufferedRequest;
  var out = [];

  while (current) {
    out.push(current);
    current = current.next;
  }

  return out;
};

(function () {
  try {
    Object.defineProperty(WritableState.prototype, 'buffer', {
      get: internalUtil.deprecate(function writableStateBufferGetter() {
        return this.getBuffer();
      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
    });
  } catch (_) {}
})(); // Test _writableState for inheritance to account for Duplex streams,
// whose prototype chain only points to Readable.


var realHasInstance;

if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
  realHasInstance = Function.prototype[Symbol.hasInstance];
  Object.defineProperty(Writable, Symbol.hasInstance, {
    value: function value(object) {
      if (realHasInstance.call(this, object)) return true;
      if (this !== Writable) return false;
      return object && object._writableState instanceof WritableState;
    }
  });
} else {
  realHasInstance = function realHasInstance(object) {
    return object instanceof this;
  };
}

function Writable(options) {
  Duplex = Duplex || require('./_stream_duplex'); // Writable ctor is applied to Duplexes, too.
  // `realHasInstance` is necessary because using plain `instanceof`
  // would return false, as no `_writableState` property is attached.
  // Trying to use the custom `instanceof` for Writable here will also break the
  // Node.js LazyTransform implementation, which has a non-trivial getter for
  // `_writableState` that would lead to infinite recursion.
  // Checking for a Stream.Duplex instance is faster here instead of inside
  // the WritableState constructor, at least with V8 6.5

  var isDuplex = this instanceof Duplex;
  if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
  this._writableState = new WritableState(options, this, isDuplex); // legacy.

  this.writable = true;

  if (options) {
    if (typeof options.write === 'function') this._write = options.write;
    if (typeof options.writev === 'function') this._writev = options.writev;
    if (typeof options.destroy === 'function') this._destroy = options.destroy;
    if (typeof options.final === 'function') this._final = options.final;
  }

  Stream.call(this);
} // Otherwise people can pipe Writable streams, which is just wrong.


Writable.prototype.pipe = function () {
  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
};

function writeAfterEnd(stream, cb) {
  var er = new ERR_STREAM_WRITE_AFTER_END(); // TODO: defer error events consistently everywhere, not just the cb

  errorOrDestroy(stream, er);
  process.nextTick(cb, er);
} // Checks that a user-supplied chunk is valid, especially for the particular
// mode the stream is in. Currently this means that `null` is never accepted
// and undefined/non-string values are only allowed in object mode.


function validChunk(stream, state, chunk, cb) {
  var er;

  if (chunk === null) {
    er = new ERR_STREAM_NULL_VALUES();
  } else if (typeof chunk !== 'string' && !state.objectMode) {
    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
  }

  if (er) {
    errorOrDestroy(stream, er);
    process.nextTick(cb, er);
    return false;
  }

  return true;
}

Writable.prototype.write = function (chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  var isBuf = !state.objectMode && _isUint8Array(chunk);

  if (isBuf && !Buffer.isBuffer(chunk)) {
    chunk = _uint8ArrayToBuffer(chunk);
  }

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
  if (typeof cb !== 'function') cb = nop;
  if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
  }
  return ret;
};

Writable.prototype.cork = function () {
  this._writableState.corked++;
};

Writable.prototype.uncork = function () {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;
    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
  }
};

Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
  // node::ParseEncoding() requires lower case.
  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
  this._writableState.defaultEncoding = encoding;
  return this;
};

Object.defineProperty(Writable.prototype, 'writableBuffer', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState && this._writableState.getBuffer();
  }
});

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
    chunk = Buffer.from(chunk, encoding);
  }

  return chunk;
}

Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState.highWaterMark;
  }
}); // if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.

function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
  if (!isBuf) {
    var newChunk = decodeChunk(state, chunk, encoding);

    if (chunk !== newChunk) {
      isBuf = true;
      encoding = 'buffer';
      chunk = newChunk;
    }
  }

  var len = state.objectMode ? 1 : chunk.length;
  state.length += len;
  var ret = state.length < state.highWaterMark; // we must ensure that previous needDrain will not be reset to false.

  if (!ret) state.needDrain = true;

  if (state.writing || state.corked) {
    var last = state.lastBufferedRequest;
    state.lastBufferedRequest = {
      chunk: chunk,
      encoding: encoding,
      isBuf: isBuf,
      callback: cb,
      next: null
    };

    if (last) {
      last.next = state.lastBufferedRequest;
    } else {
      state.bufferedRequest = state.lastBufferedRequest;
    }

    state.bufferedRequestCount += 1;
  } else {
    doWrite(stream, state, false, len, chunk, encoding, cb);
  }

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (state.destroyed) state.onwrite(new ERR_STREAM_DESTROYED('write'));else if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  --state.pendingcb;

  if (sync) {
    // defer the callback if we are being called synchronously
    // to avoid piling up things on the stack
    process.nextTick(cb, er); // this can emit finish, and it will always happen
    // after error

    process.nextTick(finishMaybe, stream, state);
    stream._writableState.errorEmitted = true;
    errorOrDestroy(stream, er);
  } else {
    // the caller expect this to happen before if
    // it is async
    cb(er);
    stream._writableState.errorEmitted = true;
    errorOrDestroy(stream, er); // this can emit finish, but finish must
    // always follow error

    finishMaybe(stream, state);
  }
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;
  if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
  onwriteStateUpdate(state);
  if (er) onwriteError(stream, state, sync, er, cb);else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(state) || stream.destroyed;

    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
      clearBuffer(stream, state);
    }

    if (sync) {
      process.nextTick(afterWrite, stream, state, finished, cb);
    } else {
      afterWrite(stream, state, finished, cb);
    }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished) onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
} // Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.


function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
} // if there's something in the buffer waiting, then process it


function clearBuffer(stream, state) {
  state.bufferProcessing = true;
  var entry = state.bufferedRequest;

  if (stream._writev && entry && entry.next) {
    // Fast case, write everything using _writev()
    var l = state.bufferedRequestCount;
    var buffer = new Array(l);
    var holder = state.corkedRequestsFree;
    holder.entry = entry;
    var count = 0;
    var allBuffers = true;

    while (entry) {
      buffer[count] = entry;
      if (!entry.isBuf) allBuffers = false;
      entry = entry.next;
      count += 1;
    }

    buffer.allBuffers = allBuffers;
    doWrite(stream, state, true, state.length, buffer, '', holder.finish); // doWrite is almost always async, defer these to save a bit of time
    // as the hot path ends with doWrite

    state.pendingcb++;
    state.lastBufferedRequest = null;

    if (holder.next) {
      state.corkedRequestsFree = holder.next;
      holder.next = null;
    } else {
      state.corkedRequestsFree = new CorkedRequest(state);
    }

    state.bufferedRequestCount = 0;
  } else {
    // Slow case, write chunks one-by-one
    while (entry) {
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;
      doWrite(stream, state, false, len, chunk, encoding, cb);
      entry = entry.next;
      state.bufferedRequestCount--; // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.

      if (state.writing) {
        break;
      }
    }

    if (entry === null) state.lastBufferedRequest = null;
  }

  state.bufferedRequest = entry;
  state.bufferProcessing = false;
}

Writable.prototype._write = function (chunk, encoding, cb) {
  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
};

Writable.prototype._writev = null;

Writable.prototype.end = function (chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding); // .end() fully uncorks

  if (state.corked) {
    state.corked = 1;
    this.uncork();
  } // ignore unnecessary end() calls.


  if (!state.ending) endWritable(this, state, cb);
  return this;
};

Object.defineProperty(Writable.prototype, 'writableLength', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    return this._writableState.length;
  }
});

function needFinish(state) {
  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
}

function callFinal(stream, state) {
  stream._final(function (err) {
    state.pendingcb--;

    if (err) {
      errorOrDestroy(stream, err);
    }

    state.prefinished = true;
    stream.emit('prefinish');
    finishMaybe(stream, state);
  });
}

function prefinish(stream, state) {
  if (!state.prefinished && !state.finalCalled) {
    if (typeof stream._final === 'function' && !state.destroyed) {
      state.pendingcb++;
      state.finalCalled = true;
      process.nextTick(callFinal, stream, state);
    } else {
      state.prefinished = true;
      stream.emit('prefinish');
    }
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(state);

  if (need) {
    prefinish(stream, state);

    if (state.pendingcb === 0) {
      state.finished = true;
      stream.emit('finish');

      if (state.autoDestroy) {
        // In case of duplex streams we need a way to detect
        // if the readable side is ready for autoDestroy as well
        var rState = stream._readableState;

        if (!rState || rState.autoDestroy && rState.endEmitted) {
          stream.destroy();
        }
      }
    }
  }

  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);

  if (cb) {
    if (state.finished) process.nextTick(cb);else stream.once('finish', cb);
  }

  state.ended = true;
  stream.writable = false;
}

function onCorkedFinish(corkReq, state, err) {
  var entry = corkReq.entry;
  corkReq.entry = null;

  while (entry) {
    var cb = entry.callback;
    state.pendingcb--;
    cb(err);
    entry = entry.next;
  } // reuse the free corkReq.


  state.corkedRequestsFree.next = corkReq;
}

Object.defineProperty(Writable.prototype, 'destroyed', {
  // making it explicit this property is not enumerable
  // because otherwise some prototype manipulation in
  // userland will fail
  enumerable: false,
  get: function get() {
    if (this._writableState === undefined) {
      return false;
    }

    return this._writableState.destroyed;
  },
  set: function set(value) {
    // we ignore the value if the stream
    // has not been initialized yet
    if (!this._writableState) {
      return;
    } // backward compatibility, the user is explicitly
    // managing destroyed


    this._writableState.destroyed = value;
  }
});
Writable.prototype.destroy = destroyImpl.destroy;
Writable.prototype._undestroy = destroyImpl.undestroy;

Writable.prototype._destroy = function (err, cb) {
  cb(err);
};
}).call(this)}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../errors":43,"./_stream_duplex":44,"./internal/streams/destroy":51,"./internal/streams/state":55,"./internal/streams/stream":56,"_process":40,"buffer":9,"inherits":36,"util-deprecate":80}],49:[function(require,module,exports){
(function (process){(function (){
'use strict';

var _Object$setPrototypeO;

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var finished = require('./end-of-stream');

var kLastResolve = Symbol('lastResolve');
var kLastReject = Symbol('lastReject');
var kError = Symbol('error');
var kEnded = Symbol('ended');
var kLastPromise = Symbol('lastPromise');
var kHandlePromise = Symbol('handlePromise');
var kStream = Symbol('stream');

function createIterResult(value, done) {
  return {
    value: value,
    done: done
  };
}

function readAndResolve(iter) {
  var resolve = iter[kLastResolve];

  if (resolve !== null) {
    var data = iter[kStream].read(); // we defer if data is null
    // we can be expecting either 'end' or
    // 'error'

    if (data !== null) {
      iter[kLastPromise] = null;
      iter[kLastResolve] = null;
      iter[kLastReject] = null;
      resolve(createIterResult(data, false));
    }
  }
}

function onReadable(iter) {
  // we wait for the next tick, because it might
  // emit an error with process.nextTick
  process.nextTick(readAndResolve, iter);
}

function wrapForNext(lastPromise, iter) {
  return function (resolve, reject) {
    lastPromise.then(function () {
      if (iter[kEnded]) {
        resolve(createIterResult(undefined, true));
        return;
      }

      iter[kHandlePromise](resolve, reject);
    }, reject);
  };
}

var AsyncIteratorPrototype = Object.getPrototypeOf(function () {});
var ReadableStreamAsyncIteratorPrototype = Object.setPrototypeOf((_Object$setPrototypeO = {
  get stream() {
    return this[kStream];
  },

  next: function next() {
    var _this = this;

    // if we have detected an error in the meanwhile
    // reject straight away
    var error = this[kError];

    if (error !== null) {
      return Promise.reject(error);
    }

    if (this[kEnded]) {
      return Promise.resolve(createIterResult(undefined, true));
    }

    if (this[kStream].destroyed) {
      // We need to defer via nextTick because if .destroy(err) is
      // called, the error will be emitted via nextTick, and
      // we cannot guarantee that there is no error lingering around
      // waiting to be emitted.
      return new Promise(function (resolve, reject) {
        process.nextTick(function () {
          if (_this[kError]) {
            reject(_this[kError]);
          } else {
            resolve(createIterResult(undefined, true));
          }
        });
      });
    } // if we have multiple next() calls
    // we will wait for the previous Promise to finish
    // this logic is optimized to support for await loops,
    // where next() is only called once at a time


    var lastPromise = this[kLastPromise];
    var promise;

    if (lastPromise) {
      promise = new Promise(wrapForNext(lastPromise, this));
    } else {
      // fast path needed to support multiple this.push()
      // without triggering the next() queue
      var data = this[kStream].read();

      if (data !== null) {
        return Promise.resolve(createIterResult(data, false));
      }

      promise = new Promise(this[kHandlePromise]);
    }

    this[kLastPromise] = promise;
    return promise;
  }
}, _defineProperty(_Object$setPrototypeO, Symbol.asyncIterator, function () {
  return this;
}), _defineProperty(_Object$setPrototypeO, "return", function _return() {
  var _this2 = this;

  // destroy(err, cb) is a private API
  // we can guarantee we have that here, because we control the
  // Readable class this is attached to
  return new Promise(function (resolve, reject) {
    _this2[kStream].destroy(null, function (err) {
      if (err) {
        reject(err);
        return;
      }

      resolve(createIterResult(undefined, true));
    });
  });
}), _Object$setPrototypeO), AsyncIteratorPrototype);

var createReadableStreamAsyncIterator = function createReadableStreamAsyncIterator(stream) {
  var _Object$create;

  var iterator = Object.create(ReadableStreamAsyncIteratorPrototype, (_Object$create = {}, _defineProperty(_Object$create, kStream, {
    value: stream,
    writable: true
  }), _defineProperty(_Object$create, kLastResolve, {
    value: null,
    writable: true
  }), _defineProperty(_Object$create, kLastReject, {
    value: null,
    writable: true
  }), _defineProperty(_Object$create, kError, {
    value: null,
    writable: true
  }), _defineProperty(_Object$create, kEnded, {
    value: stream._readableState.endEmitted,
    writable: true
  }), _defineProperty(_Object$create, kHandlePromise, {
    value: function value(resolve, reject) {
      var data = iterator[kStream].read();

      if (data) {
        iterator[kLastPromise] = null;
        iterator[kLastResolve] = null;
        iterator[kLastReject] = null;
        resolve(createIterResult(data, false));
      } else {
        iterator[kLastResolve] = resolve;
        iterator[kLastReject] = reject;
      }
    },
    writable: true
  }), _Object$create));
  iterator[kLastPromise] = null;
  finished(stream, function (err) {
    if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
      var reject = iterator[kLastReject]; // reject if we are waiting for data in the Promise
      // returned by next() and store the error

      if (reject !== null) {
        iterator[kLastPromise] = null;
        iterator[kLastResolve] = null;
        iterator[kLastReject] = null;
        reject(err);
      }

      iterator[kError] = err;
      return;
    }

    var resolve = iterator[kLastResolve];

    if (resolve !== null) {
      iterator[kLastPromise] = null;
      iterator[kLastResolve] = null;
      iterator[kLastReject] = null;
      resolve(createIterResult(undefined, true));
    }

    iterator[kEnded] = true;
  });
  stream.on('readable', onReadable.bind(null, iterator));
  return iterator;
};

module.exports = createReadableStreamAsyncIterator;
}).call(this)}).call(this,require('_process'))
},{"./end-of-stream":52,"_process":40}],50:[function(require,module,exports){
'use strict';

function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); if (enumerableOnly) symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; }); keys.push.apply(keys, symbols); } return keys; }

function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i] != null ? arguments[i] : {}; if (i % 2) { ownKeys(Object(source), true).forEach(function (key) { _defineProperty(target, key, source[key]); }); } else if (Object.getOwnPropertyDescriptors) { Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)); } else { ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } } return target; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var _require = require('buffer'),
    Buffer = _require.Buffer;

var _require2 = require('util'),
    inspect = _require2.inspect;

var custom = inspect && inspect.custom || 'inspect';

function copyBuffer(src, target, offset) {
  Buffer.prototype.copy.call(src, target, offset);
}

module.exports =
/*#__PURE__*/
function () {
  function BufferList() {
    _classCallCheck(this, BufferList);

    this.head = null;
    this.tail = null;
    this.length = 0;
  }

  _createClass(BufferList, [{
    key: "push",
    value: function push(v) {
      var entry = {
        data: v,
        next: null
      };
      if (this.length > 0) this.tail.next = entry;else this.head = entry;
      this.tail = entry;
      ++this.length;
    }
  }, {
    key: "unshift",
    value: function unshift(v) {
      var entry = {
        data: v,
        next: this.head
      };
      if (this.length === 0) this.tail = entry;
      this.head = entry;
      ++this.length;
    }
  }, {
    key: "shift",
    value: function shift() {
      if (this.length === 0) return;
      var ret = this.head.data;
      if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
      --this.length;
      return ret;
    }
  }, {
    key: "clear",
    value: function clear() {
      this.head = this.tail = null;
      this.length = 0;
    }
  }, {
    key: "join",
    value: function join(s) {
      if (this.length === 0) return '';
      var p = this.head;
      var ret = '' + p.data;

      while (p = p.next) {
        ret += s + p.data;
      }

      return ret;
    }
  }, {
    key: "concat",
    value: function concat(n) {
      if (this.length === 0) return Buffer.alloc(0);
      var ret = Buffer.allocUnsafe(n >>> 0);
      var p = this.head;
      var i = 0;

      while (p) {
        copyBuffer(p.data, ret, i);
        i += p.data.length;
        p = p.next;
      }

      return ret;
    } // Consumes a specified amount of bytes or characters from the buffered data.

  }, {
    key: "consume",
    value: function consume(n, hasStrings) {
      var ret;

      if (n < this.head.data.length) {
        // `slice` is the same for buffers and strings.
        ret = this.head.data.slice(0, n);
        this.head.data = this.head.data.slice(n);
      } else if (n === this.head.data.length) {
        // First chunk is a perfect match.
        ret = this.shift();
      } else {
        // Result spans more than one buffer.
        ret = hasStrings ? this._getString(n) : this._getBuffer(n);
      }

      return ret;
    }
  }, {
    key: "first",
    value: function first() {
      return this.head.data;
    } // Consumes a specified amount of characters from the buffered data.

  }, {
    key: "_getString",
    value: function _getString(n) {
      var p = this.head;
      var c = 1;
      var ret = p.data;
      n -= ret.length;

      while (p = p.next) {
        var str = p.data;
        var nb = n > str.length ? str.length : n;
        if (nb === str.length) ret += str;else ret += str.slice(0, n);
        n -= nb;

        if (n === 0) {
          if (nb === str.length) {
            ++c;
            if (p.next) this.head = p.next;else this.head = this.tail = null;
          } else {
            this.head = p;
            p.data = str.slice(nb);
          }

          break;
        }

        ++c;
      }

      this.length -= c;
      return ret;
    } // Consumes a specified amount of bytes from the buffered data.

  }, {
    key: "_getBuffer",
    value: function _getBuffer(n) {
      var ret = Buffer.allocUnsafe(n);
      var p = this.head;
      var c = 1;
      p.data.copy(ret);
      n -= p.data.length;

      while (p = p.next) {
        var buf = p.data;
        var nb = n > buf.length ? buf.length : n;
        buf.copy(ret, ret.length - n, 0, nb);
        n -= nb;

        if (n === 0) {
          if (nb === buf.length) {
            ++c;
            if (p.next) this.head = p.next;else this.head = this.tail = null;
          } else {
            this.head = p;
            p.data = buf.slice(nb);
          }

          break;
        }

        ++c;
      }

      this.length -= c;
      return ret;
    } // Make sure the linked list only shows the minimal necessary information.

  }, {
    key: custom,
    value: function value(_, options) {
      return inspect(this, _objectSpread({}, options, {
        // Only inspect one level.
        depth: 0,
        // It should not recurse.
        customInspect: false
      }));
    }
  }]);

  return BufferList;
}();
},{"buffer":9,"util":8}],51:[function(require,module,exports){
(function (process){(function (){
'use strict'; // undocumented cb() API, needed for core, not for public API

function destroy(err, cb) {
  var _this = this;

  var readableDestroyed = this._readableState && this._readableState.destroyed;
  var writableDestroyed = this._writableState && this._writableState.destroyed;

  if (readableDestroyed || writableDestroyed) {
    if (cb) {
      cb(err);
    } else if (err) {
      if (!this._writableState) {
        process.nextTick(emitErrorNT, this, err);
      } else if (!this._writableState.errorEmitted) {
        this._writableState.errorEmitted = true;
        process.nextTick(emitErrorNT, this, err);
      }
    }

    return this;
  } // we set destroyed to true before firing error callbacks in order
  // to make it re-entrance safe in case destroy() is called within callbacks


  if (this._readableState) {
    this._readableState.destroyed = true;
  } // if this is a duplex stream mark the writable part as destroyed as well


  if (this._writableState) {
    this._writableState.destroyed = true;
  }

  this._destroy(err || null, function (err) {
    if (!cb && err) {
      if (!_this._writableState) {
        process.nextTick(emitErrorAndCloseNT, _this, err);
      } else if (!_this._writableState.errorEmitted) {
        _this._writableState.errorEmitted = true;
        process.nextTick(emitErrorAndCloseNT, _this, err);
      } else {
        process.nextTick(emitCloseNT, _this);
      }
    } else if (cb) {
      process.nextTick(emitCloseNT, _this);
      cb(err);
    } else {
      process.nextTick(emitCloseNT, _this);
    }
  });

  return this;
}

function emitErrorAndCloseNT(self, err) {
  emitErrorNT(self, err);
  emitCloseNT(self);
}

function emitCloseNT(self) {
  if (self._writableState && !self._writableState.emitClose) return;
  if (self._readableState && !self._readableState.emitClose) return;
  self.emit('close');
}

function undestroy() {
  if (this._readableState) {
    this._readableState.destroyed = false;
    this._readableState.reading = false;
    this._readableState.ended = false;
    this._readableState.endEmitted = false;
  }

  if (this._writableState) {
    this._writableState.destroyed = false;
    this._writableState.ended = false;
    this._writableState.ending = false;
    this._writableState.finalCalled = false;
    this._writableState.prefinished = false;
    this._writableState.finished = false;
    this._writableState.errorEmitted = false;
  }
}

function emitErrorNT(self, err) {
  self.emit('error', err);
}

function errorOrDestroy(stream, err) {
  // We have tests that rely on errors being emitted
  // in the same tick, so changing this is semver major.
  // For now when you opt-in to autoDestroy we allow
  // the error to be emitted nextTick. In a future
  // semver major update we should change the default to this.
  var rState = stream._readableState;
  var wState = stream._writableState;
  if (rState && rState.autoDestroy || wState && wState.autoDestroy) stream.destroy(err);else stream.emit('error', err);
}

module.exports = {
  destroy: destroy,
  undestroy: undestroy,
  errorOrDestroy: errorOrDestroy
};
}).call(this)}).call(this,require('_process'))
},{"_process":40}],52:[function(require,module,exports){
// Ported from https://github.com/mafintosh/end-of-stream with
// permission from the author, Mathias Buus (@mafintosh).
'use strict';

var ERR_STREAM_PREMATURE_CLOSE = require('../../../errors').codes.ERR_STREAM_PREMATURE_CLOSE;

function once(callback) {
  var called = false;
  return function () {
    if (called) return;
    called = true;

    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
      args[_key] = arguments[_key];
    }

    callback.apply(this, args);
  };
}

function noop() {}

function isRequest(stream) {
  return stream.setHeader && typeof stream.abort === 'function';
}

function eos(stream, opts, callback) {
  if (typeof opts === 'function') return eos(stream, null, opts);
  if (!opts) opts = {};
  callback = once(callback || noop);
  var readable = opts.readable || opts.readable !== false && stream.readable;
  var writable = opts.writable || opts.writable !== false && stream.writable;

  var onlegacyfinish = function onlegacyfinish() {
    if (!stream.writable) onfinish();
  };

  var writableEnded = stream._writableState && stream._writableState.finished;

  var onfinish = function onfinish() {
    writable = false;
    writableEnded = true;
    if (!readable) callback.call(stream);
  };

  var readableEnded = stream._readableState && stream._readableState.endEmitted;

  var onend = function onend() {
    readable = false;
    readableEnded = true;
    if (!writable) callback.call(stream);
  };

  var onerror = function onerror(err) {
    callback.call(stream, err);
  };

  var onclose = function onclose() {
    var err;

    if (readable && !readableEnded) {
      if (!stream._readableState || !stream._readableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
      return callback.call(stream, err);
    }

    if (writable && !writableEnded) {
      if (!stream._writableState || !stream._writableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
      return callback.call(stream, err);
    }
  };

  var onrequest = function onrequest() {
    stream.req.on('finish', onfinish);
  };

  if (isRequest(stream)) {
    stream.on('complete', onfinish);
    stream.on('abort', onclose);
    if (stream.req) onrequest();else stream.on('request', onrequest);
  } else if (writable && !stream._writableState) {
    // legacy streams
    stream.on('end', onlegacyfinish);
    stream.on('close', onlegacyfinish);
  }

  stream.on('end', onend);
  stream.on('finish', onfinish);
  if (opts.error !== false) stream.on('error', onerror);
  stream.on('close', onclose);
  return function () {
    stream.removeListener('complete', onfinish);
    stream.removeListener('abort', onclose);
    stream.removeListener('request', onrequest);
    if (stream.req) stream.req.removeListener('finish', onfinish);
    stream.removeListener('end', onlegacyfinish);
    stream.removeListener('close', onlegacyfinish);
    stream.removeListener('finish', onfinish);
    stream.removeListener('end', onend);
    stream.removeListener('error', onerror);
    stream.removeListener('close', onclose);
  };
}

module.exports = eos;
},{"../../../errors":43}],53:[function(require,module,exports){
module.exports = function () {
  throw new Error('Readable.from is not available in the browser')
};

},{}],54:[function(require,module,exports){
// Ported from https://github.com/mafintosh/pump with
// permission from the author, Mathias Buus (@mafintosh).
'use strict';

var eos;

function once(callback) {
  var called = false;
  return function () {
    if (called) return;
    called = true;
    callback.apply(void 0, arguments);
  };
}

var _require$codes = require('../../../errors').codes,
    ERR_MISSING_ARGS = _require$codes.ERR_MISSING_ARGS,
    ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED;

function noop(err) {
  // Rethrow the error if it exists to avoid swallowing it
  if (err) throw err;
}

function isRequest(stream) {
  return stream.setHeader && typeof stream.abort === 'function';
}

function destroyer(stream, reading, writing, callback) {
  callback = once(callback);
  var closed = false;
  stream.on('close', function () {
    closed = true;
  });
  if (eos === undefined) eos = require('./end-of-stream');
  eos(stream, {
    readable: reading,
    writable: writing
  }, function (err) {
    if (err) return callback(err);
    closed = true;
    callback();
  });
  var destroyed = false;
  return function (err) {
    if (closed) return;
    if (destroyed) return;
    destroyed = true; // request.destroy just do .end - .abort is what we want

    if (isRequest(stream)) return stream.abort();
    if (typeof stream.destroy === 'function') return stream.destroy();
    callback(err || new ERR_STREAM_DESTROYED('pipe'));
  };
}

function call(fn) {
  fn();
}

function pipe(from, to) {
  return from.pipe(to);
}

function popCallback(streams) {
  if (!streams.length) return noop;
  if (typeof streams[streams.length - 1] !== 'function') return noop;
  return streams.pop();
}

function pipeline() {
  for (var _len = arguments.length, streams = new Array(_len), _key = 0; _key < _len; _key++) {
    streams[_key] = arguments[_key];
  }

  var callback = popCallback(streams);
  if (Array.isArray(streams[0])) streams = streams[0];

  if (streams.length < 2) {
    throw new ERR_MISSING_ARGS('streams');
  }

  var error;
  var destroys = streams.map(function (stream, i) {
    var reading = i < streams.length - 1;
    var writing = i > 0;
    return destroyer(stream, reading, writing, function (err) {
      if (!error) error = err;
      if (err) destroys.forEach(call);
      if (reading) return;
      destroys.forEach(call);
      callback(error);
    });
  });
  return streams.reduce(pipe);
}

module.exports = pipeline;
},{"../../../errors":43,"./end-of-stream":52}],55:[function(require,module,exports){
'use strict';

var ERR_INVALID_OPT_VALUE = require('../../../errors').codes.ERR_INVALID_OPT_VALUE;

function highWaterMarkFrom(options, isDuplex, duplexKey) {
  return options.highWaterMark != null ? options.highWaterMark : isDuplex ? options[duplexKey] : null;
}

function getHighWaterMark(state, options, duplexKey, isDuplex) {
  var hwm = highWaterMarkFrom(options, isDuplex, duplexKey);

  if (hwm != null) {
    if (!(isFinite(hwm) && Math.floor(hwm) === hwm) || hwm < 0) {
      var name = isDuplex ? duplexKey : 'highWaterMark';
      throw new ERR_INVALID_OPT_VALUE(name, hwm);
    }

    return Math.floor(hwm);
  } // Default value


  return state.objectMode ? 16 : 16 * 1024;
}

module.exports = {
  getHighWaterMark: getHighWaterMark
};
},{"../../../errors":43}],56:[function(require,module,exports){
module.exports = require('events').EventEmitter;

},{"events":30}],57:[function(require,module,exports){
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = exports;
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');
exports.finished = require('./lib/internal/streams/end-of-stream.js');
exports.pipeline = require('./lib/internal/streams/pipeline.js');

},{"./lib/_stream_duplex.js":44,"./lib/_stream_passthrough.js":45,"./lib/_stream_readable.js":46,"./lib/_stream_transform.js":47,"./lib/_stream_writable.js":48,"./lib/internal/streams/end-of-stream.js":52,"./lib/internal/streams/pipeline.js":54}],58:[function(require,module,exports){
/* eslint-disable node/no-deprecated-api */
var buffer = require('buffer')
var Buffer = buffer.Buffer

// alternative to using Object.keys for old browsers
function copyProps (src, dst) {
  for (var key in src) {
    dst[key] = src[key]
  }
}
if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
  module.exports = buffer
} else {
  // Copy properties from require('buffer')
  copyProps(buffer, exports)
  exports.Buffer = SafeBuffer
}

function SafeBuffer (arg, encodingOrOffset, length) {
  return Buffer(arg, encodingOrOffset, length)
}

// Copy static methods from Buffer
copyProps(Buffer, SafeBuffer)

SafeBuffer.from = function (arg, encodingOrOffset, length) {
  if (typeof arg === 'number') {
    throw new TypeError('Argument must not be a number')
  }
  return Buffer(arg, encodingOrOffset, length)
}

SafeBuffer.alloc = function (size, fill, encoding) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  var buf = Buffer(size)
  if (fill !== undefined) {
    if (typeof encoding === 'string') {
      buf.fill(fill, encoding)
    } else {
      buf.fill(fill)
    }
  } else {
    buf.fill(0)
  }
  return buf
}

SafeBuffer.allocUnsafe = function (size) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  return Buffer(size)
}

SafeBuffer.allocUnsafeSlow = function (size) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  return buffer.SlowBuffer(size)
}

},{"buffer":9}],59:[function(require,module,exports){
(function (Buffer){(function (){
/*! simple-peer. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
var debug = require('debug')('simple-peer')
var getBrowserRTC = require('get-browser-rtc')
var randombytes = require('randombytes')
var stream = require('readable-stream')
var queueMicrotask = require('queue-microtask') // TODO: remove when Node 10 is not supported

var MAX_BUFFERED_AMOUNT = 64 * 1024
var ICECOMPLETE_TIMEOUT = 5 * 1000
var CHANNEL_CLOSING_TIMEOUT = 5 * 1000

// HACK: Filter trickle lines when trickle is disabled #354
function filterTrickle (sdp) {
  return sdp.replace(/a=ice-options:trickle\s\n/g, '')
}

function makeError (err, code) {
  if (typeof err === 'string') err = new Error(err)
  if (err.error instanceof Error) err = err.error
  err.code = code
  return err
}

function warn (message) {
  console.warn(message)
}

/**
 * WebRTC peer connection. Same API as node core `net.Socket`, plus a few extra methods.
 * Duplex stream.
 * @param {Object} opts
 */
class Peer extends stream.Duplex {
  constructor (opts) {
    opts = Object.assign({
      allowHalfOpen: false
    }, opts)

    super(opts)

    this._id = randombytes(4).toString('hex').slice(0, 7)
    this._debug('new peer %o', opts)

    this.channelName = opts.initiator
      ? opts.channelName || randombytes(20).toString('hex')
      : null

    this.initiator = opts.initiator || false
    this.channelConfig = opts.channelConfig || Peer.channelConfig
    this.negotiated = this.channelConfig.negotiated
    this.config = Object.assign({}, Peer.config, opts.config)
    this.offerOptions = opts.offerOptions || {}
    this.answerOptions = opts.answerOptions || {}
    this.sdpTransform = opts.sdpTransform || (sdp => sdp)
    this.streams = opts.streams || (opts.stream ? [opts.stream] : []) // support old "stream" option
    this.trickle = opts.trickle !== undefined ? opts.trickle : true
    this.allowHalfTrickle = opts.allowHalfTrickle !== undefined ? opts.allowHalfTrickle : false
    this.iceCompleteTimeout = opts.iceCompleteTimeout || ICECOMPLETE_TIMEOUT

    this.destroyed = false
    this._connected = false

    this.remoteAddress = undefined
    this.remoteFamily = undefined
    this.remotePort = undefined
    this.localAddress = undefined
    this.localFamily = undefined
    this.localPort = undefined

    this._wrtc = (opts.wrtc && typeof opts.wrtc === 'object')
      ? opts.wrtc
      : getBrowserRTC()

    if (!this._wrtc) {
      if (typeof window === 'undefined') {
        throw makeError('No WebRTC support: Specify `opts.wrtc` option in this environment', 'ERR_WEBRTC_SUPPORT')
      } else {
        throw makeError('No WebRTC support: Not a supported browser', 'ERR_WEBRTC_SUPPORT')
      }
    }

    this._pcReady = false
    this._channelReady = false
    this._iceComplete = false // ice candidate trickle done (got null candidate)
    this._iceCompleteTimer = null // send an offer/answer anyway after some timeout
    this._channel = null
    this._pendingCandidates = []

    this._isNegotiating = this.negotiated ? false : !this.initiator // is this peer waiting for negotiation to complete?
    this._batchedNegotiation = false // batch synchronous negotiations
    this._queuedNegotiation = false // is there a queued negotiation request?
    this._sendersAwaitingStable = []
    this._senderMap = new Map()
    this._firstStable = true
    this._closingInterval = null

    this._remoteTracks = []
    this._remoteStreams = []

    this._chunk = null
    this._cb = null
    this._interval = null

    try {
      this._pc = new (this._wrtc.RTCPeerConnection)(this.config)
    } catch (err) {
      queueMicrotask(() => this.destroy(makeError(err, 'ERR_PC_CONSTRUCTOR')))
      return
    }

    // We prefer feature detection whenever possible, but sometimes that's not
    // possible for certain implementations.
    this._isReactNativeWebrtc = typeof this._pc._peerConnectionId === 'number'

    this._pc.oniceconnectionstatechange = () => {
      this._onIceStateChange()
    }
    this._pc.onicegatheringstatechange = () => {
      this._onIceStateChange()
    }
    this._pc.onconnectionstatechange = () => {
      this._onConnectionStateChange()
    }
    this._pc.onsignalingstatechange = () => {
      this._onSignalingStateChange()
    }
    this._pc.onicecandidate = event => {
      this._onIceCandidate(event)
    }

    // Other spec events, unused by this implementation:
    // - onconnectionstatechange
    // - onicecandidateerror
    // - onfingerprintfailure
    // - onnegotiationneeded

    if (this.initiator || this.negotiated) {
      this._setupData({
        channel: this._pc.createDataChannel(this.channelName, this.channelConfig)
      })
    } else {
      this._pc.ondatachannel = event => {
        this._setupData(event)
      }
    }

    if (this.streams) {
      this.streams.forEach(stream => {
        this.addStream(stream)
      })
    }
    this._pc.ontrack = event => {
      this._onTrack(event)
    }

    if (this.initiator) {
      this._needsNegotiation()
    }

    this._onFinishBound = () => {
      this._onFinish()
    }
    this.once('finish', this._onFinishBound)
  }

  get bufferSize () {
    return (this._channel && this._channel.bufferedAmount) || 0
  }

  // HACK: it's possible channel.readyState is "closing" before peer.destroy() fires
  // https://bugs.chromium.org/p/chromium/issues/detail?id=882743
  get connected () {
    return (this._connected && this._channel.readyState === 'open')
  }

  address () {
    return { port: this.localPort, family: this.localFamily, address: this.localAddress }
  }

  signal (data) {
    if (this.destroyed) throw makeError('cannot signal after peer is destroyed', 'ERR_SIGNALING')
    if (typeof data === 'string') {
      try {
        data = JSON.parse(data)
      } catch (err) {
        data = {}
      }
    }
    this._debug('signal()')

    if (data.renegotiate && this.initiator) {
      this._debug('got request to renegotiate')
      this._needsNegotiation()
    }
    if (data.transceiverRequest && this.initiator) {
      this._debug('got request for transceiver')
      this.addTransceiver(data.transceiverRequest.kind, data.transceiverRequest.init)
    }
    if (data.candidate) {
      if (this._pc.remoteDescription && this._pc.remoteDescription.type) {
        this._addIceCandidate(data.candidate)
      } else {
        this._pendingCandidates.push(data.candidate)
      }
    }
    if (data.sdp) {
      this._pc.setRemoteDescription(new (this._wrtc.RTCSessionDescription)(data))
        .then(() => {
          if (this.destroyed) return

          this._pendingCandidates.forEach(candidate => {
            this._addIceCandidate(candidate)
          })
          this._pendingCandidates = []

          if (this._pc.remoteDescription.type === 'offer') this._createAnswer()
        })
        .catch(err => {
          this.destroy(makeError(err, 'ERR_SET_REMOTE_DESCRIPTION'))
        })
    }
    if (!data.sdp && !data.candidate && !data.renegotiate && !data.transceiverRequest) {
      this.destroy(makeError('signal() called with invalid signal data', 'ERR_SIGNALING'))
    }
  }

  _addIceCandidate (candidate) {
    var iceCandidateObj = new this._wrtc.RTCIceCandidate(candidate)
    this._pc.addIceCandidate(iceCandidateObj)
      .catch(err => {
        if (!iceCandidateObj.address || iceCandidateObj.address.endsWith('.local')) {
          warn('Ignoring unsupported ICE candidate.')
        } else {
          this.destroy(makeError(err, 'ERR_ADD_ICE_CANDIDATE'))
        }
      })
  }

  /**
   * Send text/binary data to the remote peer.
   * @param {ArrayBufferView|ArrayBuffer|Buffer|string|Blob} chunk
   */
  send (chunk) {
    this._channel.send(chunk)
  }

  /**
   * Add a Transceiver to the connection.
   * @param {String} kind
   * @param {Object} init
   */
  addTransceiver (kind, init) {
    this._debug('addTransceiver()')

    if (this.initiator) {
      try {
        this._pc.addTransceiver(kind, init)
        this._needsNegotiation()
      } catch (err) {
        this.destroy(makeError(err, 'ERR_ADD_TRANSCEIVER'))
      }
    } else {
      this.emit('signal', { // request initiator to renegotiate
        transceiverRequest: { kind, init }
      })
    }
  }

  /**
   * Add a MediaStream to the connection.
   * @param {MediaStream} stream
   */
  addStream (stream) {
    this._debug('addStream()')

    stream.getTracks().forEach(track => {
      this.addTrack(track, stream)
    })
  }

  /**
   * Add a MediaStreamTrack to the connection.
   * @param {MediaStreamTrack} track
   * @param {MediaStream} stream
   */
  addTrack (track, stream) {
    this._debug('addTrack()')

    var submap = this._senderMap.get(track) || new Map() // nested Maps map [track, stream] to sender
    var sender = submap.get(stream)
    if (!sender) {
      sender = this._pc.addTrack(track, stream)
      submap.set(stream, sender)
      this._senderMap.set(track, submap)
      this._needsNegotiation()
    } else if (sender.removed) {
      throw makeError('Track has been removed. You should enable/disable tracks that you want to re-add.', 'ERR_SENDER_REMOVED')
    } else {
      throw makeError('Track has already been added to that stream.', 'ERR_SENDER_ALREADY_ADDED')
    }
  }

  /**
   * Replace a MediaStreamTrack by another in the connection.
   * @param {MediaStreamTrack} oldTrack
   * @param {MediaStreamTrack} newTrack
   * @param {MediaStream} stream
   */
  replaceTrack (oldTrack, newTrack, stream) {
    this._debug('replaceTrack()')

    var submap = this._senderMap.get(oldTrack)
    var sender = submap ? submap.get(stream) : null
    if (!sender) {
      throw makeError('Cannot replace track that was never added.', 'ERR_TRACK_NOT_ADDED')
    }
    if (newTrack) this._senderMap.set(newTrack, submap)

    if (sender.replaceTrack != null) {
      sender.replaceTrack(newTrack)
    } else {
      this.destroy(makeError('replaceTrack is not supported in this browser', 'ERR_UNSUPPORTED_REPLACETRACK'))
    }
  }

  /**
   * Remove a MediaStreamTrack from the connection.
   * @param {MediaStreamTrack} track
   * @param {MediaStream} stream
   */
  removeTrack (track, stream) {
    this._debug('removeSender()')

    var submap = this._senderMap.get(track)
    var sender = submap ? submap.get(stream) : null
    if (!sender) {
      throw makeError('Cannot remove track that was never added.', 'ERR_TRACK_NOT_ADDED')
    }
    try {
      sender.removed = true
      this._pc.removeTrack(sender)
    } catch (err) {
      if (err.name === 'NS_ERROR_UNEXPECTED') {
        this._sendersAwaitingStable.push(sender) // HACK: Firefox must wait until (signalingState === stable) https://bugzilla.mozilla.org/show_bug.cgi?id=1133874
      } else {
        this.destroy(makeError(err, 'ERR_REMOVE_TRACK'))
      }
    }
    this._needsNegotiation()
  }

  /**
   * Remove a MediaStream from the connection.
   * @param {MediaStream} stream
   */
  removeStream (stream) {
    this._debug('removeSenders()')

    stream.getTracks().forEach(track => {
      this.removeTrack(track, stream)
    })
  }

  _needsNegotiation () {
    this._debug('_needsNegotiation')
    if (this._batchedNegotiation) return // batch synchronous renegotiations
    this._batchedNegotiation = true
    queueMicrotask(() => {
      this._batchedNegotiation = false
      this._debug('starting batched negotiation')
      this.negotiate()
    })
  }

  negotiate () {
    if (this.initiator) {
      if (this._isNegotiating) {
        this._queuedNegotiation = true
        this._debug('already negotiating, queueing')
      } else {
        this._debug('start negotiation')
        setTimeout(() => { // HACK: Chrome crashes if we immediately call createOffer
          this._createOffer()
        }, 0)
      }
    } else {
      if (this._isNegotiating) {
        this._queuedNegotiation = true
        this._debug('already negotiating, queueing')
      } else {
        this._debug('requesting negotiation from initiator')
        this.emit('signal', { // request initiator to renegotiate
          renegotiate: true
        })
      }
    }
    this._isNegotiating = true
  }

  // TODO: Delete this method once readable-stream is updated to contain a default
  // implementation of destroy() that automatically calls _destroy()
  // See: https://github.com/nodejs/readable-stream/issues/283
  destroy (err) {
    this._destroy(err, () => {})
  }

  _destroy (err, cb) {
    if (this.destroyed) return

    this._debug('destroy (error: %s)', err && (err.message || err))

    this.readable = this.writable = false

    if (!this._readableState.ended) this.push(null)
    if (!this._writableState.finished) this.end()

    this.destroyed = true
    this._connected = false
    this._pcReady = false
    this._channelReady = false
    this._remoteTracks = null
    this._remoteStreams = null
    this._senderMap = null

    clearInterval(this._closingInterval)
    this._closingInterval = null

    clearInterval(this._interval)
    this._interval = null
    this._chunk = null
    this._cb = null

    if (this._onFinishBound) this.removeListener('finish', this._onFinishBound)
    this._onFinishBound = null

    if (this._channel) {
      try {
        this._channel.close()
      } catch (err) {}

      this._channel.onmessage = null
      this._channel.onopen = null
      this._channel.onclose = null
      this._channel.onerror = null
    }
    if (this._pc) {
      try {
        this._pc.close()
      } catch (err) {}

      this._pc.oniceconnectionstatechange = null
      this._pc.onicegatheringstatechange = null
      this._pc.onsignalingstatechange = null
      this._pc.onicecandidate = null
      this._pc.ontrack = null
      this._pc.ondatachannel = null
    }
    this._pc = null
    this._channel = null

    if (err) this.emit('error', err)
    this.emit('close')
    cb()
  }

  _setupData (event) {
    if (!event.channel) {
      // In some situations `pc.createDataChannel()` returns `undefined` (in wrtc),
      // which is invalid behavior. Handle it gracefully.
      // See: https://github.com/feross/simple-peer/issues/163
      return this.destroy(makeError('Data channel event is missing `channel` property', 'ERR_DATA_CHANNEL'))
    }

    this._channel = event.channel
    this._channel.binaryType = 'arraybuffer'

    if (typeof this._channel.bufferedAmountLowThreshold === 'number') {
      this._channel.bufferedAmountLowThreshold = MAX_BUFFERED_AMOUNT
    }

    this.channelName = this._channel.label

    this._channel.onmessage = event => {
      this._onChannelMessage(event)
    }
    this._channel.onbufferedamountlow = () => {
      this._onChannelBufferedAmountLow()
    }
    this._channel.onopen = () => {
      this._onChannelOpen()
    }
    this._channel.onclose = () => {
      this._onChannelClose()
    }
    this._channel.onerror = err => {
      this.destroy(makeError(err, 'ERR_DATA_CHANNEL'))
    }

    // HACK: Chrome will sometimes get stuck in readyState "closing", let's check for this condition
    // https://bugs.chromium.org/p/chromium/issues/detail?id=882743
    var isClosing = false
    this._closingInterval = setInterval(() => { // No "onclosing" event
      if (this._channel && this._channel.readyState === 'closing') {
        if (isClosing) this._onChannelClose() // closing timed out: equivalent to onclose firing
        isClosing = true
      } else {
        isClosing = false
      }
    }, CHANNEL_CLOSING_TIMEOUT)
  }

  _read () {}

  _write (chunk, encoding, cb) {
    if (this.destroyed) return cb(makeError('cannot write after peer is destroyed', 'ERR_DATA_CHANNEL'))

    if (this._connected) {
      try {
        this.send(chunk)
      } catch (err) {
        return this.destroy(makeError(err, 'ERR_DATA_CHANNEL'))
      }
      if (this._channel.bufferedAmount > MAX_BUFFERED_AMOUNT) {
        this._debug('start backpressure: bufferedAmount %d', this._channel.bufferedAmount)
        this._cb = cb
      } else {
        cb(null)
      }
    } else {
      this._debug('write before connect')
      this._chunk = chunk
      this._cb = cb
    }
  }

  // When stream finishes writing, close socket. Half open connections are not
  // supported.
  _onFinish () {
    if (this.destroyed) return

    // Wait a bit before destroying so the socket flushes.
    // TODO: is there a more reliable way to accomplish this?
    const destroySoon = () => {
      setTimeout(() => this.destroy(), 1000)
    }

    if (this._connected) {
      destroySoon()
    } else {
      this.once('connect', destroySoon)
    }
  }

  _startIceCompleteTimeout () {
    if (this.destroyed) return
    if (this._iceCompleteTimer) return
    this._debug('started iceComplete timeout')
    this._iceCompleteTimer = setTimeout(() => {
      if (!this._iceComplete) {
        this._iceComplete = true
        this._debug('iceComplete timeout completed')
        this.emit('iceTimeout')
        this.emit('_iceComplete')
      }
    }, this.iceCompleteTimeout)
  }

  _createOffer () {
    if (this.destroyed) return

    this._pc.createOffer(this.offerOptions)
      .then(offer => {
        if (this.destroyed) return
        if (!this.trickle && !this.allowHalfTrickle) offer.sdp = filterTrickle(offer.sdp)
        offer.sdp = this.sdpTransform(offer.sdp)

        const sendOffer = () => {
          if (this.destroyed) return
          var signal = this._pc.localDescription || offer
          this._debug('signal')
          this.emit('signal', {
            type: signal.type,
            sdp: signal.sdp
          })
        }

        const onSuccess = () => {
          this._debug('createOffer success')
          if (this.destroyed) return
          if (this.trickle || this._iceComplete) sendOffer()
          else this.once('_iceComplete', sendOffer) // wait for candidates
        }

        const onError = err => {
          this.destroy(makeError(err, 'ERR_SET_LOCAL_DESCRIPTION'))
        }

        this._pc.setLocalDescription(offer)
          .then(onSuccess)
          .catch(onError)
      })
      .catch(err => {
        this.destroy(makeError(err, 'ERR_CREATE_OFFER'))
      })
  }

  _requestMissingTransceivers () {
    if (this._pc.getTransceivers) {
      this._pc.getTransceivers().forEach(transceiver => {
        if (!transceiver.mid && transceiver.sender.track && !transceiver.requested) {
          transceiver.requested = true // HACK: Safari returns negotiated transceivers with a null mid
          this.addTransceiver(transceiver.sender.track.kind)
        }
      })
    }
  }

  _createAnswer () {
    if (this.destroyed) return

    this._pc.createAnswer(this.answerOptions)
      .then(answer => {
        if (this.destroyed) return
        if (!this.trickle && !this.allowHalfTrickle) answer.sdp = filterTrickle(answer.sdp)
        answer.sdp = this.sdpTransform(answer.sdp)

        const sendAnswer = () => {
          if (this.destroyed) return
          var signal = this._pc.localDescription || answer
          this._debug('signal')
          this.emit('signal', {
            type: signal.type,
            sdp: signal.sdp
          })
          if (!this.initiator) this._requestMissingTransceivers()
        }

        const onSuccess = () => {
          if (this.destroyed) return
          if (this.trickle || this._iceComplete) sendAnswer()
          else this.once('_iceComplete', sendAnswer)
        }

        const onError = err => {
          this.destroy(makeError(err, 'ERR_SET_LOCAL_DESCRIPTION'))
        }

        this._pc.setLocalDescription(answer)
          .then(onSuccess)
          .catch(onError)
      })
      .catch(err => {
        this.destroy(makeError(err, 'ERR_CREATE_ANSWER'))
      })
  }

  _onConnectionStateChange () {
    if (this.destroyed) return
    if (this._pc.connectionState === 'failed') {
      this.destroy(makeError('Connection failed.', 'ERR_CONNECTION_FAILURE'))
    }
  }

  _onIceStateChange () {
    if (this.destroyed) return
    var iceConnectionState = this._pc.iceConnectionState
    var iceGatheringState = this._pc.iceGatheringState

    this._debug(
      'iceStateChange (connection: %s) (gathering: %s)',
      iceConnectionState,
      iceGatheringState
    )
    this.emit('iceStateChange', iceConnectionState, iceGatheringState)

    if (iceConnectionState === 'connected' || iceConnectionState === 'completed') {
      this._pcReady = true
      this._maybeReady()
    }
    if (iceConnectionState === 'failed') {
      this.destroy(makeError('Ice connection failed.', 'ERR_ICE_CONNECTION_FAILURE'))
    }
    if (iceConnectionState === 'closed') {
      this.destroy(makeError('Ice connection closed.', 'ERR_ICE_CONNECTION_CLOSED'))
    }
  }

  getStats (cb) {
    // statreports can come with a value array instead of properties
    const flattenValues = report => {
      if (Object.prototype.toString.call(report.values) === '[object Array]') {
        report.values.forEach(value => {
          Object.assign(report, value)
        })
      }
      return report
    }

    // Promise-based getStats() (standard)
    if (this._pc.getStats.length === 0 || this._isReactNativeWebrtc) {
      this._pc.getStats()
        .then(res => {
          var reports = []
          res.forEach(report => {
            reports.push(flattenValues(report))
          })
          cb(null, reports)
        }, err => cb(err))

    // Single-parameter callback-based getStats() (non-standard)
    } else if (this._pc.getStats.length > 0) {
      this._pc.getStats(res => {
        // If we destroy connection in `connect` callback this code might happen to run when actual connection is already closed
        if (this.destroyed) return

        var reports = []
        res.result().forEach(result => {
          var report = {}
          result.names().forEach(name => {
            report[name] = result.stat(name)
          })
          report.id = result.id
          report.type = result.type
          report.timestamp = result.timestamp
          reports.push(flattenValues(report))
        })
        cb(null, reports)
      }, err => cb(err))

    // Unknown browser, skip getStats() since it's anyone's guess which style of
    // getStats() they implement.
    } else {
      cb(null, [])
    }
  }

  _maybeReady () {
    this._debug('maybeReady pc %s channel %s', this._pcReady, this._channelReady)
    if (this._connected || this._connecting || !this._pcReady || !this._channelReady) return

    this._connecting = true

    // HACK: We can't rely on order here, for details see https://github.com/js-platform/node-webrtc/issues/339
    const findCandidatePair = () => {
      if (this.destroyed) return

      this.getStats((err, items) => {
        if (this.destroyed) return

        // Treat getStats error as non-fatal. It's not essential.
        if (err) items = []

        var remoteCandidates = {}
        var localCandidates = {}
        var candidatePairs = {}
        var foundSelectedCandidatePair = false

        items.forEach(item => {
          // TODO: Once all browsers support the hyphenated stats report types, remove
          // the non-hypenated ones
          if (item.type === 'remotecandidate' || item.type === 'remote-candidate') {
            remoteCandidates[item.id] = item
          }
          if (item.type === 'localcandidate' || item.type === 'local-candidate') {
            localCandidates[item.id] = item
          }
          if (item.type === 'candidatepair' || item.type === 'candidate-pair') {
            candidatePairs[item.id] = item
          }
        })

        const setSelectedCandidatePair = selectedCandidatePair => {
          foundSelectedCandidatePair = true

          var local = localCandidates[selectedCandidatePair.localCandidateId]

          if (local && (local.ip || local.address)) {
            // Spec
            this.localAddress = local.ip || local.address
            this.localPort = Number(local.port)
          } else if (local && local.ipAddress) {
            // Firefox
            this.localAddress = local.ipAddress
            this.localPort = Number(local.portNumber)
          } else if (typeof selectedCandidatePair.googLocalAddress === 'string') {
            // TODO: remove this once Chrome 58 is released
            local = selectedCandidatePair.googLocalAddress.split(':')
            this.localAddress = local[0]
            this.localPort = Number(local[1])
          }
          if (this.localAddress) {
            this.localFamily = this.localAddress.includes(':') ? 'IPv6' : 'IPv4'
          }

          var remote = remoteCandidates[selectedCandidatePair.remoteCandidateId]

          if (remote && (remote.ip || remote.address)) {
            // Spec
            this.remoteAddress = remote.ip || remote.address
            this.remotePort = Number(remote.port)
          } else if (remote && remote.ipAddress) {
            // Firefox
            this.remoteAddress = remote.ipAddress
            this.remotePort = Number(remote.portNumber)
          } else if (typeof selectedCandidatePair.googRemoteAddress === 'string') {
            // TODO: remove this once Chrome 58 is released
            remote = selectedCandidatePair.googRemoteAddress.split(':')
            this.remoteAddress = remote[0]
            this.remotePort = Number(remote[1])
          }
          if (this.remoteAddress) {
            this.remoteFamily = this.remoteAddress.includes(':') ? 'IPv6' : 'IPv4'
          }

          this._debug(
            'connect local: %s:%s remote: %s:%s',
            this.localAddress, this.localPort, this.remoteAddress, this.remotePort
          )
        }

        items.forEach(item => {
          // Spec-compliant
          if (item.type === 'transport' && item.selectedCandidatePairId) {
            setSelectedCandidatePair(candidatePairs[item.selectedCandidatePairId])
          }

          // Old implementations
          if (
            (item.type === 'googCandidatePair' && item.googActiveConnection === 'true') ||
            ((item.type === 'candidatepair' || item.type === 'candidate-pair') && item.selected)
          ) {
            setSelectedCandidatePair(item)
          }
        })

        // Ignore candidate pair selection in browsers like Safari 11 that do not have any local or remote candidates
        // But wait until at least 1 candidate pair is available
        if (!foundSelectedCandidatePair && (!Object.keys(candidatePairs).length || Object.keys(localCandidates).length)) {
          setTimeout(findCandidatePair, 100)
          return
        } else {
          this._connecting = false
          this._connected = true
        }

        if (this._chunk) {
          try {
            this.send(this._chunk)
          } catch (err) {
            return this.destroy(makeError(err, 'ERR_DATA_CHANNEL'))
          }
          this._chunk = null
          this._debug('sent chunk from "write before connect"')

          var cb = this._cb
          this._cb = null
          cb(null)
        }

        // If `bufferedAmountLowThreshold` and 'onbufferedamountlow' are unsupported,
        // fallback to using setInterval to implement backpressure.
        if (typeof this._channel.bufferedAmountLowThreshold !== 'number') {
          this._interval = setInterval(() => this._onInterval(), 150)
          if (this._interval.unref) this._interval.unref()
        }

        this._debug('connect')
        this.emit('connect')
      })
    }
    findCandidatePair()
  }

  _onInterval () {
    if (!this._cb || !this._channel || this._channel.bufferedAmount > MAX_BUFFERED_AMOUNT) {
      return
    }
    this._onChannelBufferedAmountLow()
  }

  _onSignalingStateChange () {
    if (this.destroyed) return

    if (this._pc.signalingState === 'stable' && !this._firstStable) {
      this._isNegotiating = false

      // HACK: Firefox doesn't yet support removing tracks when signalingState !== 'stable'
      this._debug('flushing sender queue', this._sendersAwaitingStable)
      this._sendersAwaitingStable.forEach(sender => {
        this._pc.removeTrack(sender)
        this._queuedNegotiation = true
      })
      this._sendersAwaitingStable = []

      if (this._queuedNegotiation) {
        this._debug('flushing negotiation queue')
        this._queuedNegotiation = false
        this._needsNegotiation() // negotiate again
      }

      this._debug('negotiate')
      this.emit('negotiate')
    }
    this._firstStable = false

    this._debug('signalingStateChange %s', this._pc.signalingState)
    this.emit('signalingStateChange', this._pc.signalingState)
  }

  _onIceCandidate (event) {
    if (this.destroyed) return
    if (event.candidate && this.trickle) {
      this.emit('signal', {
        candidate: {
          candidate: event.candidate.candidate,
          sdpMLineIndex: event.candidate.sdpMLineIndex,
          sdpMid: event.candidate.sdpMid
        }
      })
    } else if (!event.candidate && !this._iceComplete) {
      this._iceComplete = true
      this.emit('_iceComplete')
    }
    // as soon as we've received one valid candidate start timeout
    if (event.candidate) {
      this._startIceCompleteTimeout()
    }
  }

  _onChannelMessage (event) {
    if (this.destroyed) return
    var data = event.data
    if (data instanceof ArrayBuffer) data = Buffer.from(data)
    this.push(data)
  }

  _onChannelBufferedAmountLow () {
    if (this.destroyed || !this._cb) return
    this._debug('ending backpressure: bufferedAmount %d', this._channel.bufferedAmount)
    var cb = this._cb
    this._cb = null
    cb(null)
  }

  _onChannelOpen () {
    if (this._connected || this.destroyed) return
    this._debug('on channel open')
    this._channelReady = true
    this._maybeReady()
  }

  _onChannelClose () {
    if (this.destroyed) return
    this._debug('on channel close')
    this.destroy()
  }

  _onTrack (event) {
    if (this.destroyed) return

    event.streams.forEach(eventStream => {
      this._debug('on track')
      this.emit('track', event.track, eventStream)

      this._remoteTracks.push({
        track: event.track,
        stream: eventStream
      })

      if (this._remoteStreams.some(remoteStream => {
        return remoteStream.id === eventStream.id
      })) return // Only fire one 'stream' event, even though there may be multiple tracks per stream

      this._remoteStreams.push(eventStream)
      queueMicrotask(() => {
        this.emit('stream', eventStream) // ensure all tracks have been added
      })
    })
  }

  _debug () {
    var args = [].slice.call(arguments)
    args[0] = '[' + this._id + '] ' + args[0]
    debug.apply(null, args)
  }
}

Peer.WEBRTC_SUPPORT = !!getBrowserRTC()

/**
 * Expose peer and data channel config for overriding all Peer
 * instances. Otherwise, just set opts.config or opts.channelConfig
 * when constructing a Peer.
 */
Peer.config = {
  iceServers: [
    {
      urls: 'stun:stun.l.google.com:19302'
    },
    {
      urls: 'stun:global.stun.twilio.com:3478?transport=udp'
    }
  ],
  sdpSemantics: 'unified-plan'
}

Peer.channelConfig = {}

module.exports = Peer

}).call(this)}).call(this,require("buffer").Buffer)
},{"buffer":9,"debug":60,"get-browser-rtc":31,"queue-microtask":41,"randombytes":42,"readable-stream":57}],60:[function(require,module,exports){
arguments[4][24][0].apply(exports,arguments)
},{"./common":61,"_process":40,"dup":24}],61:[function(require,module,exports){
arguments[4][25][0].apply(exports,arguments)
},{"dup":25,"ms":62}],62:[function(require,module,exports){
arguments[4][26][0].apply(exports,arguments)
},{"dup":26}],63:[function(require,module,exports){

/**
 * Module dependencies.
 */

var url = require('./url');
var parser = require('socket.io-parser');
var Manager = require('./manager');
var debug = require('debug')('socket.io-client');

/**
 * Module exports.
 */

module.exports = exports = lookup;

/**
 * Managers cache.
 */

var cache = exports.managers = {};

/**
 * Looks up an existing `Manager` for multiplexing.
 * If the user summons:
 *
 *   `io('http://localhost/a');`
 *   `io('http://localhost/b');`
 *
 * We reuse the existing instance based on same scheme/port/host,
 * and we initialize sockets for each namespace.
 *
 * @api public
 */

function lookup (uri, opts) {
  if (typeof uri === 'object') {
    opts = uri;
    uri = undefined;
  }

  opts = opts || {};

  var parsed = url(uri);
  var source = parsed.source;
  var id = parsed.id;
  var path = parsed.path;
  var sameNamespace = cache[id] && path in cache[id].nsps;
  var newConnection = opts.forceNew || opts['force new connection'] ||
                      false === opts.multiplex || sameNamespace;

  var io;

  if (newConnection) {
    debug('ignoring socket cache for %s', source);
    io = Manager(source, opts);
  } else {
    if (!cache[id]) {
      debug('new io instance for %s', source);
      cache[id] = Manager(source, opts);
    }
    io = cache[id];
  }
  if (parsed.query && !opts.query) {
    opts.query = parsed.query;
  }
  return io.socket(parsed.path, opts);
}

/**
 * Protocol version.
 *
 * @api public
 */

exports.protocol = parser.protocol;

/**
 * `connect`.
 *
 * @param {String} uri
 * @api public
 */

exports.connect = lookup;

/**
 * Expose constructors for standalone build.
 *
 * @api public
 */

exports.Manager = require('./manager');
exports.Socket = require('./socket');

},{"./manager":64,"./socket":66,"./url":67,"debug":68,"socket.io-parser":72}],64:[function(require,module,exports){

/**
 * Module dependencies.
 */

var eio = require('engine.io-client');
var Socket = require('./socket');
var Emitter = require('component-emitter');
var parser = require('socket.io-parser');
var on = require('./on');
var bind = require('component-bind');
var debug = require('debug')('socket.io-client:manager');
var indexOf = require('indexof');
var Backoff = require('backo2');

/**
 * IE6+ hasOwnProperty
 */

var has = Object.prototype.hasOwnProperty;

/**
 * Module exports
 */

module.exports = Manager;

/**
 * `Manager` constructor.
 *
 * @param {String} engine instance or engine uri/opts
 * @param {Object} options
 * @api public
 */

function Manager (uri, opts) {
  if (!(this instanceof Manager)) return new Manager(uri, opts);
  if (uri && ('object' === typeof uri)) {
    opts = uri;
    uri = undefined;
  }
  opts = opts || {};

  opts.path = opts.path || '/socket.io';
  this.nsps = {};
  this.subs = [];
  this.opts = opts;
  this.reconnection(opts.reconnection !== false);
  this.reconnectionAttempts(opts.reconnectionAttempts || Infinity);
  this.reconnectionDelay(opts.reconnectionDelay || 1000);
  this.reconnectionDelayMax(opts.reconnectionDelayMax || 5000);
  this.randomizationFactor(opts.randomizationFactor || 0.5);
  this.backoff = new Backoff({
    min: this.reconnectionDelay(),
    max: this.reconnectionDelayMax(),
    jitter: this.randomizationFactor()
  });
  this.timeout(null == opts.timeout ? 20000 : opts.timeout);
  this.readyState = 'closed';
  this.uri = uri;
  this.connecting = [];
  this.lastPing = null;
  this.encoding = false;
  this.packetBuffer = [];
  var _parser = opts.parser || parser;
  this.encoder = new _parser.Encoder();
  this.decoder = new _parser.Decoder();
  this.autoConnect = opts.autoConnect !== false;
  if (this.autoConnect) this.open();
}

/**
 * Propagate given event to sockets and emit on `this`
 *
 * @api private
 */

Manager.prototype.emitAll = function () {
  this.emit.apply(this, arguments);
  for (var nsp in this.nsps) {
    if (has.call(this.nsps, nsp)) {
      this.nsps[nsp].emit.apply(this.nsps[nsp], arguments);
    }
  }
};

/**
 * Update `socket.id` of all sockets
 *
 * @api private
 */

Manager.prototype.updateSocketIds = function () {
  for (var nsp in this.nsps) {
    if (has.call(this.nsps, nsp)) {
      this.nsps[nsp].id = this.generateId(nsp);
    }
  }
};

/**
 * generate `socket.id` for the given `nsp`
 *
 * @param {String} nsp
 * @return {String}
 * @api private
 */

Manager.prototype.generateId = function (nsp) {
  return (nsp === '/' ? '' : (nsp + '#')) + this.engine.id;
};

/**
 * Mix in `Emitter`.
 */

Emitter(Manager.prototype);

/**
 * Sets the `reconnection` config.
 *
 * @param {Boolean} true/false if it should automatically reconnect
 * @return {Manager} self or value
 * @api public
 */

Manager.prototype.reconnection = function (v) {
  if (!arguments.length) return this._reconnection;
  this._reconnection = !!v;
  return this;
};

/**
 * Sets the reconnection attempts config.
 *
 * @param {Number} max reconnection attempts before giving up
 * @return {Manager} self or value
 * @api public
 */

Manager.prototype.reconnectionAttempts = function (v) {
  if (!arguments.length) return this._reconnectionAttempts;
  this._reconnectionAttempts = v;
  return this;
};

/**
 * Sets the delay between reconnections.
 *
 * @param {Number} delay
 * @return {Manager} self or value
 * @api public
 */

Manager.prototype.reconnectionDelay = function (v) {
  if (!arguments.length) return this._reconnectionDelay;
  this._reconnectionDelay = v;
  this.backoff && this.backoff.setMin(v);
  return this;
};

Manager.prototype.randomizationFactor = function (v) {
  if (!arguments.length) return this._randomizationFactor;
  this._randomizationFactor = v;
  this.backoff && this.backoff.setJitter(v);
  return this;
};

/**
 * Sets the maximum delay between reconnections.
 *
 * @param {Number} delay
 * @return {Manager} self or value
 * @api public
 */

Manager.prototype.reconnectionDelayMax = function (v) {
  if (!arguments.length) return this._reconnectionDelayMax;
  this._reconnectionDelayMax = v;
  this.backoff && this.backoff.setMax(v);
  return this;
};

/**
 * Sets the connection timeout. `false` to disable
 *
 * @return {Manager} self or value
 * @api public
 */

Manager.prototype.timeout = function (v) {
  if (!arguments.length) return this._timeout;
  this._timeout = v;
  return this;
};

/**
 * Starts trying to reconnect if reconnection is enabled and we have not
 * started reconnecting yet
 *
 * @api private
 */

Manager.prototype.maybeReconnectOnOpen = function () {
  // Only try to reconnect if it's the first time we're connecting
  if (!this.reconnecting && this._reconnection && this.backoff.attempts === 0) {
    // keeps reconnection from firing twice for the same reconnection loop
    this.reconnect();
  }
};

/**
 * Sets the current transport `socket`.
 *
 * @param {Function} optional, callback
 * @return {Manager} self
 * @api public
 */

Manager.prototype.open =
Manager.prototype.connect = function (fn, opts) {
  debug('readyState %s', this.readyState);
  if (~this.readyState.indexOf('open')) return this;

  debug('opening %s', this.uri);
  this.engine = eio(this.uri, this.opts);
  var socket = this.engine;
  var self = this;
  this.readyState = 'opening';
  this.skipReconnect = false;

  // emit `open`
  var openSub = on(socket, 'open', function () {
    self.onopen();
    fn && fn();
  });

  // emit `connect_error`
  var errorSub = on(socket, 'error', function (data) {
    debug('connect_error');
    self.cleanup();
    self.readyState = 'closed';
    self.emitAll('connect_error', data);
    if (fn) {
      var err = new Error('Connection error');
      err.data = data;
      fn(err);
    } else {
      // Only do this if there is no fn to handle the error
      self.maybeReconnectOnOpen();
    }
  });

  // emit `connect_timeout`
  if (false !== this._timeout) {
    var timeout = this._timeout;
    debug('connect attempt will timeout after %d', timeout);

    // set timer
    var timer = setTimeout(function () {
      debug('connect attempt timed out after %d', timeout);
      openSub.destroy();
      socket.close();
      socket.emit('error', 'timeout');
      self.emitAll('connect_timeout', timeout);
    }, timeout);

    this.subs.push({
      destroy: function () {
        clearTimeout(timer);
      }
    });
  }

  this.subs.push(openSub);
  this.subs.push(errorSub);

  return this;
};

/**
 * Called upon transport open.
 *
 * @api private
 */

Manager.prototype.onopen = function () {
  debug('open');

  // clear old subs
  this.cleanup();

  // mark as open
  this.readyState = 'open';
  this.emit('open');

  // add new subs
  var socket = this.engine;
  this.subs.push(on(socket, 'data', bind(this, 'ondata')));
  this.subs.push(on(socket, 'ping', bind(this, 'onping')));
  this.subs.push(on(socket, 'pong', bind(this, 'onpong')));
  this.subs.push(on(socket, 'error', bind(this, 'onerror')));
  this.subs.push(on(socket, 'close', bind(this, 'onclose')));
  this.subs.push(on(this.decoder, 'decoded', bind(this, 'ondecoded')));
};

/**
 * Called upon a ping.
 *
 * @api private
 */

Manager.prototype.onping = function () {
  this.lastPing = new Date();
  this.emitAll('ping');
};

/**
 * Called upon a packet.
 *
 * @api private
 */

Manager.prototype.onpong = function () {
  this.emitAll('pong', new Date() - this.lastPing);
};

/**
 * Called with data.
 *
 * @api private
 */

Manager.prototype.ondata = function (data) {
  this.decoder.add(data);
};

/**
 * Called when parser fully decodes a packet.
 *
 * @api private
 */

Manager.prototype.ondecoded = function (packet) {
  this.emit('packet', packet);
};

/**
 * Called upon socket error.
 *
 * @api private
 */

Manager.prototype.onerror = function (err) {
  debug('error', err);
  this.emitAll('error', err);
};

/**
 * Creates a new socket for the given `nsp`.
 *
 * @return {Socket}
 * @api public
 */

Manager.prototype.socket = function (nsp, opts) {
  var socket = this.nsps[nsp];
  if (!socket) {
    socket = new Socket(this, nsp, opts);
    this.nsps[nsp] = socket;
    var self = this;
    socket.on('connecting', onConnecting);
    socket.on('connect', function () {
      socket.id = self.generateId(nsp);
    });

    if (this.autoConnect) {
      // manually call here since connecting event is fired before listening
      onConnecting();
    }
  }

  function onConnecting () {
    if (!~indexOf(self.connecting, socket)) {
      self.connecting.push(socket);
    }
  }

  return socket;
};

/**
 * Called upon a socket close.
 *
 * @param {Socket} socket
 */

Manager.prototype.destroy = function (socket) {
  var index = indexOf(this.connecting, socket);
  if (~index) this.connecting.splice(index, 1);
  if (this.connecting.length) return;

  this.close();
};

/**
 * Writes a packet.
 *
 * @param {Object} packet
 * @api private
 */

Manager.prototype.packet = function (packet) {
  debug('writing packet %j', packet);
  var self = this;
  if (packet.query && packet.type === 0) packet.nsp += '?' + packet.query;

  if (!self.encoding) {
    // encode, then write to engine with result
    self.encoding = true;
    this.encoder.encode(packet, function (encodedPackets) {
      for (var i = 0; i < encodedPackets.length; i++) {
        self.engine.write(encodedPackets[i], packet.options);
      }
      self.encoding = false;
      self.processPacketQueue();
    });
  } else { // add packet to the queue
    self.packetBuffer.push(packet);
  }
};

/**
 * If packet buffer is non-empty, begins encoding the
 * next packet in line.
 *
 * @api private
 */

Manager.prototype.processPacketQueue = function () {
  if (this.packetBuffer.length > 0 && !this.encoding) {
    var pack = this.packetBuffer.shift();
    this.packet(pack);
  }
};

/**
 * Clean up transport subscriptions and packet buffer.
 *
 * @api private
 */

Manager.prototype.cleanup = function () {
  debug('cleanup');

  var subsLength = this.subs.length;
  for (var i = 0; i < subsLength; i++) {
    var sub = this.subs.shift();
    sub.destroy();
  }

  this.packetBuffer = [];
  this.encoding = false;
  this.lastPing = null;

  this.decoder.destroy();
};

/**
 * Close the current socket.
 *
 * @api private
 */

Manager.prototype.close =
Manager.prototype.disconnect = function () {
  debug('disconnect');
  this.skipReconnect = true;
  this.reconnecting = false;
  if ('opening' === this.readyState) {
    // `onclose` will not fire because
    // an open event never happened
    this.cleanup();
  }
  this.backoff.reset();
  this.readyState = 'closed';
  if (this.engine) this.engine.close();
};

/**
 * Called upon engine close.
 *
 * @api private
 */

Manager.prototype.onclose = function (reason) {
  debug('onclose');

  this.cleanup();
  this.backoff.reset();
  this.readyState = 'closed';
  this.emit('close', reason);

  if (this._reconnection && !this.skipReconnect) {
    this.reconnect();
  }
};

/**
 * Attempt a reconnection.
 *
 * @api private
 */

Manager.prototype.reconnect = function () {
  if (this.reconnecting || this.skipReconnect) return this;

  var self = this;

  if (this.backoff.attempts >= this._reconnectionAttempts) {
    debug('reconnect failed');
    this.backoff.reset();
    this.emitAll('reconnect_failed');
    this.reconnecting = false;
  } else {
    var delay = this.backoff.duration();
    debug('will wait %dms before reconnect attempt', delay);

    this.reconnecting = true;
    var timer = setTimeout(function () {
      if (self.skipReconnect) return;

      debug('attempting reconnect');
      self.emitAll('reconnect_attempt', self.backoff.attempts);
      self.emitAll('reconnecting', self.backoff.attempts);

      // check again for the case socket closed in above events
      if (self.skipReconnect) return;

      self.open(function (err) {
        if (err) {
          debug('reconnect attempt error');
          self.reconnecting = false;
          self.reconnect();
          self.emitAll('reconnect_error', err.data);
        } else {
          debug('reconnect success');
          self.onreconnect();
        }
      });
    }, delay);

    this.subs.push({
      destroy: function () {
        clearTimeout(timer);
      }
    });
  }
};

/**
 * Called upon successful reconnect.
 *
 * @api private
 */

Manager.prototype.onreconnect = function () {
  var attempt = this.backoff.attempts;
  this.reconnecting = false;
  this.backoff.reset();
  this.updateSocketIds();
  this.emitAll('reconnect', attempt);
};

},{"./on":65,"./socket":66,"backo2":4,"component-bind":10,"component-emitter":11,"debug":68,"engine.io-client":14,"indexof":35,"socket.io-parser":72}],65:[function(require,module,exports){

/**
 * Module exports.
 */

module.exports = on;

/**
 * Helper for subscriptions.
 *
 * @param {Object|EventEmitter} obj with `Emitter` mixin or `EventEmitter`
 * @param {String} event name
 * @param {Function} callback
 * @api public
 */

function on (obj, ev, fn) {
  obj.on(ev, fn);
  return {
    destroy: function () {
      obj.removeListener(ev, fn);
    }
  };
}

},{}],66:[function(require,module,exports){

/**
 * Module dependencies.
 */

var parser = require('socket.io-parser');
var Emitter = require('component-emitter');
var toArray = require('to-array');
var on = require('./on');
var bind = require('component-bind');
var debug = require('debug')('socket.io-client:socket');
var parseqs = require('parseqs');
var hasBin = require('has-binary2');

/**
 * Module exports.
 */

module.exports = exports = Socket;

/**
 * Internal events (blacklisted).
 * These events can't be emitted by the user.
 *
 * @api private
 */

var events = {
  connect: 1,
  connect_error: 1,
  connect_timeout: 1,
  connecting: 1,
  disconnect: 1,
  error: 1,
  reconnect: 1,
  reconnect_attempt: 1,
  reconnect_failed: 1,
  reconnect_error: 1,
  reconnecting: 1,
  ping: 1,
  pong: 1
};

/**
 * Shortcut to `Emitter#emit`.
 */

var emit = Emitter.prototype.emit;

/**
 * `Socket` constructor.
 *
 * @api public
 */

function Socket (io, nsp, opts) {
  this.io = io;
  this.nsp = nsp;
  this.json = this; // compat
  this.ids = 0;
  this.acks = {};
  this.receiveBuffer = [];
  this.sendBuffer = [];
  this.connected = false;
  this.disconnected = true;
  this.flags = {};
  if (opts && opts.query) {
    this.query = opts.query;
  }
  if (this.io.autoConnect) this.open();
}

/**
 * Mix in `Emitter`.
 */

Emitter(Socket.prototype);

/**
 * Subscribe to open, close and packet events
 *
 * @api private
 */

Socket.prototype.subEvents = function () {
  if (this.subs) return;

  var io = this.io;
  this.subs = [
    on(io, 'open', bind(this, 'onopen')),
    on(io, 'packet', bind(this, 'onpacket')),
    on(io, 'close', bind(this, 'onclose'))
  ];
};

/**
 * "Opens" the socket.
 *
 * @api public
 */

Socket.prototype.open =
Socket.prototype.connect = function () {
  if (this.connected) return this;

  this.subEvents();
  this.io.open(); // ensure open
  if ('open' === this.io.readyState) this.onopen();
  this.emit('connecting');
  return this;
};

/**
 * Sends a `message` event.
 *
 * @return {Socket} self
 * @api public
 */

Socket.prototype.send = function () {
  var args = toArray(arguments);
  args.unshift('message');
  this.emit.apply(this, args);
  return this;
};

/**
 * Override `emit`.
 * If the event is in `events`, it's emitted normally.
 *
 * @param {String} event name
 * @return {Socket} self
 * @api public
 */

Socket.prototype.emit = function (ev) {
  if (events.hasOwnProperty(ev)) {
    emit.apply(this, arguments);
    return this;
  }

  var args = toArray(arguments);
  var packet = {
    type: (this.flags.binary !== undefined ? this.flags.binary : hasBin(args)) ? parser.BINARY_EVENT : parser.EVENT,
    data: args
  };

  packet.options = {};
  packet.options.compress = !this.flags || false !== this.flags.compress;

  // event ack callback
  if ('function' === typeof args[args.length - 1]) {
    debug('emitting packet with ack id %d', this.ids);
    this.acks[this.ids] = args.pop();
    packet.id = this.ids++;
  }

  if (this.connected) {
    this.packet(packet);
  } else {
    this.sendBuffer.push(packet);
  }

  this.flags = {};

  return this;
};

/**
 * Sends a packet.
 *
 * @param {Object} packet
 * @api private
 */

Socket.prototype.packet = function (packet) {
  packet.nsp = this.nsp;
  this.io.packet(packet);
};

/**
 * Called upon engine `open`.
 *
 * @api private
 */

Socket.prototype.onopen = function () {
  debug('transport is open - connecting');

  // write connect packet if necessary
  if ('/' !== this.nsp) {
    if (this.query) {
      var query = typeof this.query === 'object' ? parseqs.encode(this.query) : this.query;
      debug('sending connect packet with query %s', query);
      this.packet({type: parser.CONNECT, query: query});
    } else {
      this.packet({type: parser.CONNECT});
    }
  }
};

/**
 * Called upon engine `close`.
 *
 * @param {String} reason
 * @api private
 */

Socket.prototype.onclose = function (reason) {
  debug('close (%s)', reason);
  this.connected = false;
  this.disconnected = true;
  delete this.id;
  this.emit('disconnect', reason);
};

/**
 * Called with socket packet.
 *
 * @param {Object} packet
 * @api private
 */

Socket.prototype.onpacket = function (packet) {
  var sameNamespace = packet.nsp === this.nsp;
  var rootNamespaceError = packet.type === parser.ERROR && packet.nsp === '/';

  if (!sameNamespace && !rootNamespaceError) return;

  switch (packet.type) {
    case parser.CONNECT:
      this.onconnect();
      break;

    case parser.EVENT:
      this.onevent(packet);
      break;

    case parser.BINARY_EVENT:
      this.onevent(packet);
      break;

    case parser.ACK:
      this.onack(packet);
      break;

    case parser.BINARY_ACK:
      this.onack(packet);
      break;

    case parser.DISCONNECT:
      this.ondisconnect();
      break;

    case parser.ERROR:
      this.emit('error', packet.data);
      break;
  }
};

/**
 * Called upon a server event.
 *
 * @param {Object} packet
 * @api private
 */

Socket.prototype.onevent = function (packet) {
  var args = packet.data || [];
  debug('emitting event %j', args);

  if (null != packet.id) {
    debug('attaching ack callback to event');
    args.push(this.ack(packet.id));
  }

  if (this.connected) {
    emit.apply(this, args);
  } else {
    this.receiveBuffer.push(args);
  }
};

/**
 * Produces an ack callback to emit with an event.
 *
 * @api private
 */

Socket.prototype.ack = function (id) {
  var self = this;
  var sent = false;
  return function () {
    // prevent double callbacks
    if (sent) return;
    sent = true;
    var args = toArray(arguments);
    debug('sending ack %j', args);

    self.packet({
      type: hasBin(args) ? parser.BINARY_ACK : parser.ACK,
      id: id,
      data: args
    });
  };
};

/**
 * Called upon a server acknowlegement.
 *
 * @param {Object} packet
 * @api private
 */

Socket.prototype.onack = function (packet) {
  var ack = this.acks[packet.id];
  if ('function' === typeof ack) {
    debug('calling ack %s with %j', packet.id, packet.data);
    ack.apply(this, packet.data);
    delete this.acks[packet.id];
  } else {
    debug('bad ack %s', packet.id);
  }
};

/**
 * Called upon server connect.
 *
 * @api private
 */

Socket.prototype.onconnect = function () {
  this.connected = true;
  this.disconnected = false;
  this.emit('connect');
  this.emitBuffered();
};

/**
 * Emit buffered events (received and emitted).
 *
 * @api private
 */

Socket.prototype.emitBuffered = function () {
  var i;
  for (i = 0; i < this.receiveBuffer.length; i++) {
    emit.apply(this, this.receiveBuffer[i]);
  }
  this.receiveBuffer = [];

  for (i = 0; i < this.sendBuffer.length; i++) {
    this.packet(this.sendBuffer[i]);
  }
  this.sendBuffer = [];
};

/**
 * Called upon server disconnect.
 *
 * @api private
 */

Socket.prototype.ondisconnect = function () {
  debug('server disconnect (%s)', this.nsp);
  this.destroy();
  this.onclose('io server disconnect');
};

/**
 * Called upon forced client/server side disconnections,
 * this method ensures the manager stops tracking us and
 * that reconnections don't get triggered for this.
 *
 * @api private.
 */

Socket.prototype.destroy = function () {
  if (this.subs) {
    // clean subscriptions to avoid reconnections
    for (var i = 0; i < this.subs.length; i++) {
      this.subs[i].destroy();
    }
    this.subs = null;
  }

  this.io.destroy(this);
};

/**
 * Disconnects the socket manually.
 *
 * @return {Socket} self
 * @api public
 */

Socket.prototype.close =
Socket.prototype.disconnect = function () {
  if (this.connected) {
    debug('performing disconnect (%s)', this.nsp);
    this.packet({ type: parser.DISCONNECT });
  }

  // remove socket from pool
  this.destroy();

  if (this.connected) {
    // fire events
    this.onclose('io client disconnect');
  }
  return this;
};

/**
 * Sets the compress flag.
 *
 * @param {Boolean} if `true`, compresses the sending data
 * @return {Socket} self
 * @api public
 */

Socket.prototype.compress = function (compress) {
  this.flags.compress = compress;
  return this;
};

/**
 * Sets the binary flag
 *
 * @param {Boolean} whether the emitted data contains binary
 * @return {Socket} self
 * @api public
 */

Socket.prototype.binary = function (binary) {
  this.flags.binary = binary;
  return this;
};

},{"./on":65,"component-bind":10,"component-emitter":11,"debug":68,"has-binary2":32,"parseqs":38,"socket.io-parser":72,"to-array":79}],67:[function(require,module,exports){

/**
 * Module dependencies.
 */

var parseuri = require('parseuri');
var debug = require('debug')('socket.io-client:url');

/**
 * Module exports.
 */

module.exports = url;

/**
 * URL parser.
 *
 * @param {String} url
 * @param {Object} An object meant to mimic window.location.
 *                 Defaults to window.location.
 * @api public
 */

function url (uri, loc) {
  var obj = uri;

  // default to window.location
  loc = loc || (typeof location !== 'undefined' && location);
  if (null == uri) uri = loc.protocol + '//' + loc.host;

  // relative path support
  if ('string' === typeof uri) {
    if ('/' === uri.charAt(0)) {
      if ('/' === uri.charAt(1)) {
        uri = loc.protocol + uri;
      } else {
        uri = loc.host + uri;
      }
    }

    if (!/^(https?|wss?):\/\//.test(uri)) {
      debug('protocol-less url %s', uri);
      if ('undefined' !== typeof loc) {
        uri = loc.protocol + '//' + uri;
      } else {
        uri = 'https://' + uri;
      }
    }

    // parse
    debug('parse %s', uri);
    obj = parseuri(uri);
  }

  // make sure we treat `localhost:80` and `localhost` equally
  if (!obj.port) {
    if (/^(http|ws)$/.test(obj.protocol)) {
      obj.port = '80';
    } else if (/^(http|ws)s$/.test(obj.protocol)) {
      obj.port = '443';
    }
  }

  obj.path = obj.path || '/';

  var ipv6 = obj.host.indexOf(':') !== -1;
  var host = ipv6 ? '[' + obj.host + ']' : obj.host;

  // define unique id
  obj.id = obj.protocol + '://' + host + ':' + obj.port;
  // define href
  obj.href = obj.protocol + '://' + host + (loc && loc.port === obj.port ? '' : (':' + obj.port));

  return obj;
}

},{"debug":68,"parseuri":39}],68:[function(require,module,exports){
arguments[4][24][0].apply(exports,arguments)
},{"./common":69,"_process":40,"dup":24}],69:[function(require,module,exports){
arguments[4][25][0].apply(exports,arguments)
},{"dup":25,"ms":70}],70:[function(require,module,exports){
arguments[4][26][0].apply(exports,arguments)
},{"dup":26}],71:[function(require,module,exports){
/*global Blob,File*/

/**
 * Module requirements
 */

var isArray = require('isarray');
var isBuf = require('./is-buffer');
var toString = Object.prototype.toString;
var withNativeBlob = typeof Blob === 'function' || (typeof Blob !== 'undefined' && toString.call(Blob) === '[object BlobConstructor]');
var withNativeFile = typeof File === 'function' || (typeof File !== 'undefined' && toString.call(File) === '[object FileConstructor]');

/**
 * Replaces every Buffer | ArrayBuffer in packet with a numbered placeholder.
 * Anything with blobs or files should be fed through removeBlobs before coming
 * here.
 *
 * @param {Object} packet - socket.io event packet
 * @return {Object} with deconstructed packet and list of buffers
 * @api public
 */

exports.deconstructPacket = function(packet) {
  var buffers = [];
  var packetData = packet.data;
  var pack = packet;
  pack.data = _deconstructPacket(packetData, buffers);
  pack.attachments = buffers.length; // number of binary 'attachments'
  return {packet: pack, buffers: buffers};
};

function _deconstructPacket(data, buffers) {
  if (!data) return data;

  if (isBuf(data)) {
    var placeholder = { _placeholder: true, num: buffers.length };
    buffers.push(data);
    return placeholder;
  } else if (isArray(data)) {
    var newData = new Array(data.length);
    for (var i = 0; i < data.length; i++) {
      newData[i] = _deconstructPacket(data[i], buffers);
    }
    return newData;
  } else if (typeof data === 'object' && !(data instanceof Date)) {
    var newData = {};
    for (var key in data) {
      newData[key] = _deconstructPacket(data[key], buffers);
    }
    return newData;
  }
  return data;
}

/**
 * Reconstructs a binary packet from its placeholder packet and buffers
 *
 * @param {Object} packet - event packet with placeholders
 * @param {Array} buffers - binary buffers to put in placeholder positions
 * @return {Object} reconstructed packet
 * @api public
 */

exports.reconstructPacket = function(packet, buffers) {
  packet.data = _reconstructPacket(packet.data, buffers);
  packet.attachments = undefined; // no longer useful
  return packet;
};

function _reconstructPacket(data, buffers) {
  if (!data) return data;

  if (data && data._placeholder) {
    return buffers[data.num]; // appropriate buffer (should be natural order anyway)
  } else if (isArray(data)) {
    for (var i = 0; i < data.length; i++) {
      data[i] = _reconstructPacket(data[i], buffers);
    }
  } else if (typeof data === 'object') {
    for (var key in data) {
      data[key] = _reconstructPacket(data[key], buffers);
    }
  }

  return data;
}

/**
 * Asynchronously removes Blobs or Files from data via
 * FileReader's readAsArrayBuffer method. Used before encoding
 * data as msgpack. Calls callback with the blobless data.
 *
 * @param {Object} data
 * @param {Function} callback
 * @api private
 */

exports.removeBlobs = function(data, callback) {
  function _removeBlobs(obj, curKey, containingObject) {
    if (!obj) return obj;

    // convert any blob
    if ((withNativeBlob && obj instanceof Blob) ||
        (withNativeFile && obj instanceof File)) {
      pendingBlobs++;

      // async filereader
      var fileReader = new FileReader();
      fileReader.onload = function() { // this.result == arraybuffer
        if (containingObject) {
          containingObject[curKey] = this.result;
        }
        else {
          bloblessData = this.result;
        }

        // if nothing pending its callback time
        if(! --pendingBlobs) {
          callback(bloblessData);
        }
      };

      fileReader.readAsArrayBuffer(obj); // blob -> arraybuffer
    } else if (isArray(obj)) { // handle array
      for (var i = 0; i < obj.length; i++) {
        _removeBlobs(obj[i], i, obj);
      }
    } else if (typeof obj === 'object' && !isBuf(obj)) { // and object
      for (var key in obj) {
        _removeBlobs(obj[key], key, obj);
      }
    }
  }

  var pendingBlobs = 0;
  var bloblessData = data;
  _removeBlobs(bloblessData);
  if (!pendingBlobs) {
    callback(bloblessData);
  }
};

},{"./is-buffer":73,"isarray":37}],72:[function(require,module,exports){

/**
 * Module dependencies.
 */

var debug = require('debug')('socket.io-parser');
var Emitter = require('component-emitter');
var binary = require('./binary');
var isArray = require('isarray');
var isBuf = require('./is-buffer');

/**
 * Protocol version.
 *
 * @api public
 */

exports.protocol = 4;

/**
 * Packet types.
 *
 * @api public
 */

exports.types = [
  'CONNECT',
  'DISCONNECT',
  'EVENT',
  'ACK',
  'ERROR',
  'BINARY_EVENT',
  'BINARY_ACK'
];

/**
 * Packet type `connect`.
 *
 * @api public
 */

exports.CONNECT = 0;

/**
 * Packet type `disconnect`.
 *
 * @api public
 */

exports.DISCONNECT = 1;

/**
 * Packet type `event`.
 *
 * @api public
 */

exports.EVENT = 2;

/**
 * Packet type `ack`.
 *
 * @api public
 */

exports.ACK = 3;

/**
 * Packet type `error`.
 *
 * @api public
 */

exports.ERROR = 4;

/**
 * Packet type 'binary event'
 *
 * @api public
 */

exports.BINARY_EVENT = 5;

/**
 * Packet type `binary ack`. For acks with binary arguments.
 *
 * @api public
 */

exports.BINARY_ACK = 6;

/**
 * Encoder constructor.
 *
 * @api public
 */

exports.Encoder = Encoder;

/**
 * Decoder constructor.
 *
 * @api public
 */

exports.Decoder = Decoder;

/**
 * A socket.io Encoder instance
 *
 * @api public
 */

function Encoder() {}

var ERROR_PACKET = exports.ERROR + '"encode error"';

/**
 * Encode a packet as a single string if non-binary, or as a
 * buffer sequence, depending on packet type.
 *
 * @param {Object} obj - packet object
 * @param {Function} callback - function to handle encodings (likely engine.write)
 * @return Calls callback with Array of encodings
 * @api public
 */

Encoder.prototype.encode = function(obj, callback){
  debug('encoding packet %j', obj);

  if (exports.BINARY_EVENT === obj.type || exports.BINARY_ACK === obj.type) {
    encodeAsBinary(obj, callback);
  } else {
    var encoding = encodeAsString(obj);
    callback([encoding]);
  }
};

/**
 * Encode packet as string.
 *
 * @param {Object} packet
 * @return {String} encoded
 * @api private
 */

function encodeAsString(obj) {

  // first is type
  var str = '' + obj.type;

  // attachments if we have them
  if (exports.BINARY_EVENT === obj.type || exports.BINARY_ACK === obj.type) {
    str += obj.attachments + '-';
  }

  // if we have a namespace other than `/`
  // we append it followed by a comma `,`
  if (obj.nsp && '/' !== obj.nsp) {
    str += obj.nsp + ',';
  }

  // immediately followed by the id
  if (null != obj.id) {
    str += obj.id;
  }

  // json data
  if (null != obj.data) {
    var payload = tryStringify(obj.data);
    if (payload !== false) {
      str += payload;
    } else {
      return ERROR_PACKET;
    }
  }

  debug('encoded %j as %s', obj, str);
  return str;
}

function tryStringify(str) {
  try {
    return JSON.stringify(str);
  } catch(e){
    return false;
  }
}

/**
 * Encode packet as 'buffer sequence' by removing blobs, and
 * deconstructing packet into object with placeholders and
 * a list of buffers.
 *
 * @param {Object} packet
 * @return {Buffer} encoded
 * @api private
 */

function encodeAsBinary(obj, callback) {

  function writeEncoding(bloblessData) {
    var deconstruction = binary.deconstructPacket(bloblessData);
    var pack = encodeAsString(deconstruction.packet);
    var buffers = deconstruction.buffers;

    buffers.unshift(pack); // add packet info to beginning of data list
    callback(buffers); // write all the buffers
  }

  binary.removeBlobs(obj, writeEncoding);
}

/**
 * A socket.io Decoder instance
 *
 * @return {Object} decoder
 * @api public
 */

function Decoder() {
  this.reconstructor = null;
}

/**
 * Mix in `Emitter` with Decoder.
 */

Emitter(Decoder.prototype);

/**
 * Decodes an encoded packet string into packet JSON.
 *
 * @param {String} obj - encoded packet
 * @return {Object} packet
 * @api public
 */

Decoder.prototype.add = function(obj) {
  var packet;
  if (typeof obj === 'string') {
    packet = decodeString(obj);
    if (exports.BINARY_EVENT === packet.type || exports.BINARY_ACK === packet.type) { // binary packet's json
      this.reconstructor = new BinaryReconstructor(packet);

      // no attachments, labeled binary but no binary data to follow
      if (this.reconstructor.reconPack.attachments === 0) {
        this.emit('decoded', packet);
      }
    } else { // non-binary full packet
      this.emit('decoded', packet);
    }
  } else if (isBuf(obj) || obj.base64) { // raw binary data
    if (!this.reconstructor) {
      throw new Error('got binary data when not reconstructing a packet');
    } else {
      packet = this.reconstructor.takeBinaryData(obj);
      if (packet) { // received final buffer
        this.reconstructor = null;
        this.emit('decoded', packet);
      }
    }
  } else {
    throw new Error('Unknown type: ' + obj);
  }
};

/**
 * Decode a packet String (JSON data)
 *
 * @param {String} str
 * @return {Object} packet
 * @api private
 */

function decodeString(str) {
  var i = 0;
  // look up type
  var p = {
    type: Number(str.charAt(0))
  };

  if (null == exports.types[p.type]) {
    return error('unknown packet type ' + p.type);
  }

  // look up attachments if type binary
  if (exports.BINARY_EVENT === p.type || exports.BINARY_ACK === p.type) {
    var buf = '';
    while (str.charAt(++i) !== '-') {
      buf += str.charAt(i);
      if (i == str.length) break;
    }
    if (buf != Number(buf) || str.charAt(i) !== '-') {
      throw new Error('Illegal attachments');
    }
    p.attachments = Number(buf);
  }

  // look up namespace (if any)
  if ('/' === str.charAt(i + 1)) {
    p.nsp = '';
    while (++i) {
      var c = str.charAt(i);
      if (',' === c) break;
      p.nsp += c;
      if (i === str.length) break;
    }
  } else {
    p.nsp = '/';
  }

  // look up id
  var next = str.charAt(i + 1);
  if ('' !== next && Number(next) == next) {
    p.id = '';
    while (++i) {
      var c = str.charAt(i);
      if (null == c || Number(c) != c) {
        --i;
        break;
      }
      p.id += str.charAt(i);
      if (i === str.length) break;
    }
    p.id = Number(p.id);
  }

  // look up json data
  if (str.charAt(++i)) {
    var payload = tryParse(str.substr(i));
    var isPayloadValid = payload !== false && (p.type === exports.ERROR || isArray(payload));
    if (isPayloadValid) {
      p.data = payload;
    } else {
      return error('invalid payload');
    }
  }

  debug('decoded %s as %j', str, p);
  return p;
}

function tryParse(str) {
  try {
    return JSON.parse(str);
  } catch(e){
    return false;
  }
}

/**
 * Deallocates a parser's resources
 *
 * @api public
 */

Decoder.prototype.destroy = function() {
  if (this.reconstructor) {
    this.reconstructor.finishedReconstruction();
  }
};

/**
 * A manager of a binary event's 'buffer sequence'. Should
 * be constructed whenever a packet of type BINARY_EVENT is
 * decoded.
 *
 * @param {Object} packet
 * @return {BinaryReconstructor} initialized reconstructor
 * @api private
 */

function BinaryReconstructor(packet) {
  this.reconPack = packet;
  this.buffers = [];
}

/**
 * Method to be called when binary data received from connection
 * after a BINARY_EVENT packet.
 *
 * @param {Buffer | ArrayBuffer} binData - the raw binary data received
 * @return {null | Object} returns null if more binary data is expected or
 *   a reconstructed packet object if all buffers have been received.
 * @api private
 */

BinaryReconstructor.prototype.takeBinaryData = function(binData) {
  this.buffers.push(binData);
  if (this.buffers.length === this.reconPack.attachments) { // done with buffer list
    var packet = binary.reconstructPacket(this.reconPack, this.buffers);
    this.finishedReconstruction();
    return packet;
  }
  return null;
};

/**
 * Cleans up binary packet reconstruction variables.
 *
 * @api private
 */

BinaryReconstructor.prototype.finishedReconstruction = function() {
  this.reconPack = null;
  this.buffers = [];
};

function error(msg) {
  return {
    type: exports.ERROR,
    data: 'parser error: ' + msg
  };
}

},{"./binary":71,"./is-buffer":73,"component-emitter":11,"debug":74,"isarray":37}],73:[function(require,module,exports){
(function (Buffer){(function (){

module.exports = isBuf;

var withNativeBuffer = typeof Buffer === 'function' && typeof Buffer.isBuffer === 'function';
var withNativeArrayBuffer = typeof ArrayBuffer === 'function';

var isView = function (obj) {
  return typeof ArrayBuffer.isView === 'function' ? ArrayBuffer.isView(obj) : (obj.buffer instanceof ArrayBuffer);
};

/**
 * Returns true if obj is a buffer or an arraybuffer.
 *
 * @api private
 */

function isBuf(obj) {
  return (withNativeBuffer && Buffer.isBuffer(obj)) ||
          (withNativeArrayBuffer && (obj instanceof ArrayBuffer || isView(obj)));
}

}).call(this)}).call(this,require("buffer").Buffer)
},{"buffer":9}],74:[function(require,module,exports){
(function (process){(function (){
/**
 * This is the web browser implementation of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = require('./debug');
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
exports.storage = 'undefined' != typeof chrome
               && 'undefined' != typeof chrome.storage
                  ? chrome.storage.local
                  : localstorage();

/**
 * Colors.
 */

exports.colors = [
  '#0000CC', '#0000FF', '#0033CC', '#0033FF', '#0066CC', '#0066FF', '#0099CC',
  '#0099FF', '#00CC00', '#00CC33', '#00CC66', '#00CC99', '#00CCCC', '#00CCFF',
  '#3300CC', '#3300FF', '#3333CC', '#3333FF', '#3366CC', '#3366FF', '#3399CC',
  '#3399FF', '#33CC00', '#33CC33', '#33CC66', '#33CC99', '#33CCCC', '#33CCFF',
  '#6600CC', '#6600FF', '#6633CC', '#6633FF', '#66CC00', '#66CC33', '#9900CC',
  '#9900FF', '#9933CC', '#9933FF', '#99CC00', '#99CC33', '#CC0000', '#CC0033',
  '#CC0066', '#CC0099', '#CC00CC', '#CC00FF', '#CC3300', '#CC3333', '#CC3366',
  '#CC3399', '#CC33CC', '#CC33FF', '#CC6600', '#CC6633', '#CC9900', '#CC9933',
  '#CCCC00', '#CCCC33', '#FF0000', '#FF0033', '#FF0066', '#FF0099', '#FF00CC',
  '#FF00FF', '#FF3300', '#FF3333', '#FF3366', '#FF3399', '#FF33CC', '#FF33FF',
  '#FF6600', '#FF6633', '#FF9900', '#FF9933', '#FFCC00', '#FFCC33'
];

/**
 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 * and the Firebug extension (any Firefox version) are known
 * to support "%c" CSS customizations.
 *
 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 */

function useColors() {
  // NB: In an Electron preload script, document will be defined but not fully
  // initialized. Since we know we're in Chrome, we'll just detect this case
  // explicitly
  if (typeof window !== 'undefined' && window.process && window.process.type === 'renderer') {
    return true;
  }

  // Internet Explorer and Edge do not support colors.
  if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
    return false;
  }

  // is webkit? http://stackoverflow.com/a/16459606/376773
  // document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
  return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
    // is firebug? http://stackoverflow.com/a/398120/376773
    (typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
    // is firefox >= v31?
    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31) ||
    // double check webkit in userAgent just in case we are in a worker
    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
}

/**
 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 */

exports.formatters.j = function(v) {
  try {
    return JSON.stringify(v);
  } catch (err) {
    return '[UnexpectedJSONParseError]: ' + err.message;
  }
};


/**
 * Colorize log arguments if enabled.
 *
 * @api public
 */

function formatArgs(args) {
  var useColors = this.useColors;

  args[0] = (useColors ? '%c' : '')
    + this.namespace
    + (useColors ? ' %c' : ' ')
    + args[0]
    + (useColors ? '%c ' : ' ')
    + '+' + exports.humanize(this.diff);

  if (!useColors) return;

  var c = 'color: ' + this.color;
  args.splice(1, 0, c, 'color: inherit')

  // the final "%c" is somewhat tricky, because there could be other
  // arguments passed either before or after the %c, so we need to
  // figure out the correct index to insert the CSS into
  var index = 0;
  var lastC = 0;
  args[0].replace(/%[a-zA-Z%]/g, function(match) {
    if ('%%' === match) return;
    index++;
    if ('%c' === match) {
      // we only are interested in the *last* %c
      // (the user may have provided their own)
      lastC = index;
    }
  });

  args.splice(lastC, 0, c);
}

/**
 * Invokes `console.log()` when available.
 * No-op when `console.log` is not a "function".
 *
 * @api public
 */

function log() {
  // this hackery is required for IE8/9, where
  // the `console.log` function doesn't have 'apply'
  return 'object' === typeof console
    && console.log
    && Function.prototype.apply.call(console.log, console, arguments);
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */

function save(namespaces) {
  try {
    if (null == namespaces) {
      exports.storage.removeItem('debug');
    } else {
      exports.storage.debug = namespaces;
    }
  } catch(e) {}
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
  var r;
  try {
    r = exports.storage.debug;
  } catch(e) {}

  // If debug isn't set in LS, and we're in Electron, try to load $DEBUG
  if (!r && typeof process !== 'undefined' && 'env' in process) {
    r = process.env.DEBUG;
  }

  return r;
}

/**
 * Enable namespaces listed in `localStorage.debug` initially.
 */

exports.enable(load());

/**
 * Localstorage attempts to return the localstorage.
 *
 * This is necessary because safari throws
 * when a user disables cookies/localstorage
 * and you attempt to access it.
 *
 * @return {LocalStorage}
 * @api private
 */

function localstorage() {
  try {
    return window.localStorage;
  } catch (e) {}
}

}).call(this)}).call(this,require('_process'))
},{"./debug":75,"_process":40}],75:[function(require,module,exports){

/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = createDebug.debug = createDebug['default'] = createDebug;
exports.coerce = coerce;
exports.disable = disable;
exports.enable = enable;
exports.enabled = enabled;
exports.humanize = require('ms');

/**
 * Active `debug` instances.
 */
exports.instances = [];

/**
 * The currently active debug mode names, and names to skip.
 */

exports.names = [];
exports.skips = [];

/**
 * Map of special "%n" handling functions, for the debug "format" argument.
 *
 * Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
 */

exports.formatters = {};

/**
 * Select a color.
 * @param {String} namespace
 * @return {Number}
 * @api private
 */

function selectColor(namespace) {
  var hash = 0, i;

  for (i in namespace) {
    hash  = ((hash << 5) - hash) + namespace.charCodeAt(i);
    hash |= 0; // Convert to 32bit integer
  }

  return exports.colors[Math.abs(hash) % exports.colors.length];
}

/**
 * Create a debugger with the given `namespace`.
 *
 * @param {String} namespace
 * @return {Function}
 * @api public
 */

function createDebug(namespace) {

  var prevTime;

  function debug() {
    // disabled?
    if (!debug.enabled) return;

    var self = debug;

    // set `diff` timestamp
    var curr = +new Date();
    var ms = curr - (prevTime || curr);
    self.diff = ms;
    self.prev = prevTime;
    self.curr = curr;
    prevTime = curr;

    // turn the `arguments` into a proper Array
    var args = new Array(arguments.length);
    for (var i = 0; i < args.length; i++) {
      args[i] = arguments[i];
    }

    args[0] = exports.coerce(args[0]);

    if ('string' !== typeof args[0]) {
      // anything else let's inspect with %O
      args.unshift('%O');
    }

    // apply any `formatters` transformations
    var index = 0;
    args[0] = args[0].replace(/%([a-zA-Z%])/g, function(match, format) {
      // if we encounter an escaped % then don't increase the array index
      if (match === '%%') return match;
      index++;
      var formatter = exports.formatters[format];
      if ('function' === typeof formatter) {
        var val = args[index];
        match = formatter.call(self, val);

        // now we need to remove `args[index]` since it's inlined in the `format`
        args.splice(index, 1);
        index--;
      }
      return match;
    });

    // apply env-specific formatting (colors, etc.)
    exports.formatArgs.call(self, args);

    var logFn = debug.log || exports.log || console.log.bind(console);
    logFn.apply(self, args);
  }

  debug.namespace = namespace;
  debug.enabled = exports.enabled(namespace);
  debug.useColors = exports.useColors();
  debug.color = selectColor(namespace);
  debug.destroy = destroy;

  // env-specific initialization logic for debug instances
  if ('function' === typeof exports.init) {
    exports.init(debug);
  }

  exports.instances.push(debug);

  return debug;
}

function destroy () {
  var index = exports.instances.indexOf(this);
  if (index !== -1) {
    exports.instances.splice(index, 1);
    return true;
  } else {
    return false;
  }
}

/**
 * Enables a debug mode by namespaces. This can include modes
 * separated by a colon and wildcards.
 *
 * @param {String} namespaces
 * @api public
 */

function enable(namespaces) {
  exports.save(namespaces);

  exports.names = [];
  exports.skips = [];

  var i;
  var split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
  var len = split.length;

  for (i = 0; i < len; i++) {
    if (!split[i]) continue; // ignore empty strings
    namespaces = split[i].replace(/\*/g, '.*?');
    if (namespaces[0] === '-') {
      exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
    } else {
      exports.names.push(new RegExp('^' + namespaces + '$'));
    }
  }

  for (i = 0; i < exports.instances.length; i++) {
    var instance = exports.instances[i];
    instance.enabled = exports.enabled(instance.namespace);
  }
}

/**
 * Disable debug output.
 *
 * @api public
 */

function disable() {
  exports.enable('');
}

/**
 * Returns true if the given mode name is enabled, false otherwise.
 *
 * @param {String} name
 * @return {Boolean}
 * @api public
 */

function enabled(name) {
  if (name[name.length - 1] === '*') {
    return true;
  }
  var i, len;
  for (i = 0, len = exports.skips.length; i < len; i++) {
    if (exports.skips[i].test(name)) {
      return false;
    }
  }
  for (i = 0, len = exports.names.length; i < len; i++) {
    if (exports.names[i].test(name)) {
      return true;
    }
  }
  return false;
}

/**
 * Coerce `val`.
 *
 * @param {Mixed} val
 * @return {Mixed}
 * @api private
 */

function coerce(val) {
  if (val instanceof Error) return val.stack || val.message;
  return val;
}

},{"ms":76}],76:[function(require,module,exports){
/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var y = d * 365.25;

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} [options]
 * @throws {Error} throw an error if val is not a non-empty string or a number
 * @return {String|Number}
 * @api public
 */

module.exports = function(val, options) {
  options = options || {};
  var type = typeof val;
  if (type === 'string' && val.length > 0) {
    return parse(val);
  } else if (type === 'number' && isNaN(val) === false) {
    return options.long ? fmtLong(val) : fmtShort(val);
  }
  throw new Error(
    'val is not a non-empty string or a valid number. val=' +
      JSON.stringify(val)
  );
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

function parse(str) {
  str = String(str);
  if (str.length > 100) {
    return;
  }
  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(
    str
  );
  if (!match) {
    return;
  }
  var n = parseFloat(match[1]);
  var type = (match[2] || 'ms').toLowerCase();
  switch (type) {
    case 'years':
    case 'year':
    case 'yrs':
    case 'yr':
    case 'y':
      return n * y;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m;
    case 'seconds':
    case 'second':
    case 'secs':
    case 'sec':
    case 's':
      return n * s;
    case 'milliseconds':
    case 'millisecond':
    case 'msecs':
    case 'msec':
    case 'ms':
      return n;
    default:
      return undefined;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtShort(ms) {
  if (ms >= d) {
    return Math.round(ms / d) + 'd';
  }
  if (ms >= h) {
    return Math.round(ms / h) + 'h';
  }
  if (ms >= m) {
    return Math.round(ms / m) + 'm';
  }
  if (ms >= s) {
    return Math.round(ms / s) + 's';
  }
  return ms + 'ms';
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtLong(ms) {
  return plural(ms, d, 'day') ||
    plural(ms, h, 'hour') ||
    plural(ms, m, 'minute') ||
    plural(ms, s, 'second') ||
    ms + ' ms';
}

/**
 * Pluralization helper.
 */

function plural(ms, n, name) {
  if (ms < n) {
    return;
  }
  if (ms < n * 1.5) {
    return Math.floor(ms / n) + ' ' + name;
  }
  return Math.ceil(ms / n) + ' ' + name + 's';
}

},{}],77:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';

/*<replacement>*/

var Buffer = require('safe-buffer').Buffer;
/*</replacement>*/

var isEncoding = Buffer.isEncoding || function (encoding) {
  encoding = '' + encoding;
  switch (encoding && encoding.toLowerCase()) {
    case 'hex':case 'utf8':case 'utf-8':case 'ascii':case 'binary':case 'base64':case 'ucs2':case 'ucs-2':case 'utf16le':case 'utf-16le':case 'raw':
      return true;
    default:
      return false;
  }
};

function _normalizeEncoding(enc) {
  if (!enc) return 'utf8';
  var retried;
  while (true) {
    switch (enc) {
      case 'utf8':
      case 'utf-8':
        return 'utf8';
      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return 'utf16le';
      case 'latin1':
      case 'binary':
        return 'latin1';
      case 'base64':
      case 'ascii':
      case 'hex':
        return enc;
      default:
        if (retried) return; // undefined
        enc = ('' + enc).toLowerCase();
        retried = true;
    }
  }
};

// Do not cache `Buffer.isEncoding` when checking encoding names as some
// modules monkey-patch it to support additional encodings
function normalizeEncoding(enc) {
  var nenc = _normalizeEncoding(enc);
  if (typeof nenc !== 'string' && (Buffer.isEncoding === isEncoding || !isEncoding(enc))) throw new Error('Unknown encoding: ' + enc);
  return nenc || enc;
}

// StringDecoder provides an interface for efficiently splitting a series of
// buffers into a series of JS strings without breaking apart multi-byte
// characters.
exports.StringDecoder = StringDecoder;
function StringDecoder(encoding) {
  this.encoding = normalizeEncoding(encoding);
  var nb;
  switch (this.encoding) {
    case 'utf16le':
      this.text = utf16Text;
      this.end = utf16End;
      nb = 4;
      break;
    case 'utf8':
      this.fillLast = utf8FillLast;
      nb = 4;
      break;
    case 'base64':
      this.text = base64Text;
      this.end = base64End;
      nb = 3;
      break;
    default:
      this.write = simpleWrite;
      this.end = simpleEnd;
      return;
  }
  this.lastNeed = 0;
  this.lastTotal = 0;
  this.lastChar = Buffer.allocUnsafe(nb);
}

StringDecoder.prototype.write = function (buf) {
  if (buf.length === 0) return '';
  var r;
  var i;
  if (this.lastNeed) {
    r = this.fillLast(buf);
    if (r === undefined) return '';
    i = this.lastNeed;
    this.lastNeed = 0;
  } else {
    i = 0;
  }
  if (i < buf.length) return r ? r + this.text(buf, i) : this.text(buf, i);
  return r || '';
};

StringDecoder.prototype.end = utf8End;

// Returns only complete characters in a Buffer
StringDecoder.prototype.text = utf8Text;

// Attempts to complete a partial non-UTF-8 character using bytes from a Buffer
StringDecoder.prototype.fillLast = function (buf) {
  if (this.lastNeed <= buf.length) {
    buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, this.lastNeed);
    return this.lastChar.toString(this.encoding, 0, this.lastTotal);
  }
  buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, buf.length);
  this.lastNeed -= buf.length;
};

// Checks the type of a UTF-8 byte, whether it's ASCII, a leading byte, or a
// continuation byte. If an invalid byte is detected, -2 is returned.
function utf8CheckByte(byte) {
  if (byte <= 0x7F) return 0;else if (byte >> 5 === 0x06) return 2;else if (byte >> 4 === 0x0E) return 3;else if (byte >> 3 === 0x1E) return 4;
  return byte >> 6 === 0x02 ? -1 : -2;
}

// Checks at most 3 bytes at the end of a Buffer in order to detect an
// incomplete multi-byte UTF-8 character. The total number of bytes (2, 3, or 4)
// needed to complete the UTF-8 character (if applicable) are returned.
function utf8CheckIncomplete(self, buf, i) {
  var j = buf.length - 1;
  if (j < i) return 0;
  var nb = utf8CheckByte(buf[j]);
  if (nb >= 0) {
    if (nb > 0) self.lastNeed = nb - 1;
    return nb;
  }
  if (--j < i || nb === -2) return 0;
  nb = utf8CheckByte(buf[j]);
  if (nb >= 0) {
    if (nb > 0) self.lastNeed = nb - 2;
    return nb;
  }
  if (--j < i || nb === -2) return 0;
  nb = utf8CheckByte(buf[j]);
  if (nb >= 0) {
    if (nb > 0) {
      if (nb === 2) nb = 0;else self.lastNeed = nb - 3;
    }
    return nb;
  }
  return 0;
}

// Validates as many continuation bytes for a multi-byte UTF-8 character as
// needed or are available. If we see a non-continuation byte where we expect
// one, we "replace" the validated continuation bytes we've seen so far with
// a single UTF-8 replacement character ('\ufffd'), to match v8's UTF-8 decoding
// behavior. The continuation byte check is included three times in the case
// where all of the continuation bytes for a character exist in the same buffer.
// It is also done this way as a slight performance increase instead of using a
// loop.
function utf8CheckExtraBytes(self, buf, p) {
  if ((buf[0] & 0xC0) !== 0x80) {
    self.lastNeed = 0;
    return '\ufffd';
  }
  if (self.lastNeed > 1 && buf.length > 1) {
    if ((buf[1] & 0xC0) !== 0x80) {
      self.lastNeed = 1;
      return '\ufffd';
    }
    if (self.lastNeed > 2 && buf.length > 2) {
      if ((buf[2] & 0xC0) !== 0x80) {
        self.lastNeed = 2;
        return '\ufffd';
      }
    }
  }
}

// Attempts to complete a multi-byte UTF-8 character using bytes from a Buffer.
function utf8FillLast(buf) {
  var p = this.lastTotal - this.lastNeed;
  var r = utf8CheckExtraBytes(this, buf, p);
  if (r !== undefined) return r;
  if (this.lastNeed <= buf.length) {
    buf.copy(this.lastChar, p, 0, this.lastNeed);
    return this.lastChar.toString(this.encoding, 0, this.lastTotal);
  }
  buf.copy(this.lastChar, p, 0, buf.length);
  this.lastNeed -= buf.length;
}

// Returns all complete UTF-8 characters in a Buffer. If the Buffer ended on a
// partial character, the character's bytes are buffered until the required
// number of bytes are available.
function utf8Text(buf, i) {
  var total = utf8CheckIncomplete(this, buf, i);
  if (!this.lastNeed) return buf.toString('utf8', i);
  this.lastTotal = total;
  var end = buf.length - (total - this.lastNeed);
  buf.copy(this.lastChar, 0, end);
  return buf.toString('utf8', i, end);
}

// For UTF-8, a replacement character is added when ending on a partial
// character.
function utf8End(buf) {
  var r = buf && buf.length ? this.write(buf) : '';
  if (this.lastNeed) return r + '\ufffd';
  return r;
}

// UTF-16LE typically needs two bytes per character, but even if we have an even
// number of bytes available, we need to check if we end on a leading/high
// surrogate. In that case, we need to wait for the next two bytes in order to
// decode the last character properly.
function utf16Text(buf, i) {
  if ((buf.length - i) % 2 === 0) {
    var r = buf.toString('utf16le', i);
    if (r) {
      var c = r.charCodeAt(r.length - 1);
      if (c >= 0xD800 && c <= 0xDBFF) {
        this.lastNeed = 2;
        this.lastTotal = 4;
        this.lastChar[0] = buf[buf.length - 2];
        this.lastChar[1] = buf[buf.length - 1];
        return r.slice(0, -1);
      }
    }
    return r;
  }
  this.lastNeed = 1;
  this.lastTotal = 2;
  this.lastChar[0] = buf[buf.length - 1];
  return buf.toString('utf16le', i, buf.length - 1);
}

// For UTF-16LE we do not explicitly append special replacement characters if we
// end on a partial character, we simply let v8 handle that.
function utf16End(buf) {
  var r = buf && buf.length ? this.write(buf) : '';
  if (this.lastNeed) {
    var end = this.lastTotal - this.lastNeed;
    return r + this.lastChar.toString('utf16le', 0, end);
  }
  return r;
}

function base64Text(buf, i) {
  var n = (buf.length - i) % 3;
  if (n === 0) return buf.toString('base64', i);
  this.lastNeed = 3 - n;
  this.lastTotal = 3;
  if (n === 1) {
    this.lastChar[0] = buf[buf.length - 1];
  } else {
    this.lastChar[0] = buf[buf.length - 2];
    this.lastChar[1] = buf[buf.length - 1];
  }
  return buf.toString('base64', i, buf.length - n);
}

function base64End(buf) {
  var r = buf && buf.length ? this.write(buf) : '';
  if (this.lastNeed) return r + this.lastChar.toString('base64', 0, 3 - this.lastNeed);
  return r;
}

// Pass bytes on through for single-byte encodings (e.g. ascii, latin1, hex)
function simpleWrite(buf) {
  return buf.toString(this.encoding);
}

function simpleEnd(buf) {
  return buf && buf.length ? this.write(buf) : '';
}
},{"safe-buffer":78}],78:[function(require,module,exports){
/*! safe-buffer. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
/* eslint-disable node/no-deprecated-api */
var buffer = require('buffer')
var Buffer = buffer.Buffer

// alternative to using Object.keys for old browsers
function copyProps (src, dst) {
  for (var key in src) {
    dst[key] = src[key]
  }
}
if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
  module.exports = buffer
} else {
  // Copy properties from require('buffer')
  copyProps(buffer, exports)
  exports.Buffer = SafeBuffer
}

function SafeBuffer (arg, encodingOrOffset, length) {
  return Buffer(arg, encodingOrOffset, length)
}

SafeBuffer.prototype = Object.create(Buffer.prototype)

// Copy static methods from Buffer
copyProps(Buffer, SafeBuffer)

SafeBuffer.from = function (arg, encodingOrOffset, length) {
  if (typeof arg === 'number') {
    throw new TypeError('Argument must not be a number')
  }
  return Buffer(arg, encodingOrOffset, length)
}

SafeBuffer.alloc = function (size, fill, encoding) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  var buf = Buffer(size)
  if (fill !== undefined) {
    if (typeof encoding === 'string') {
      buf.fill(fill, encoding)
    } else {
      buf.fill(fill)
    }
  } else {
    buf.fill(0)
  }
  return buf
}

SafeBuffer.allocUnsafe = function (size) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  return Buffer(size)
}

SafeBuffer.allocUnsafeSlow = function (size) {
  if (typeof size !== 'number') {
    throw new TypeError('Argument must be a number')
  }
  return buffer.SlowBuffer(size)
}

},{"buffer":9}],79:[function(require,module,exports){
module.exports = toArray

function toArray(list, index) {
    var array = []

    index = index || 0

    for (var i = index || 0; i < list.length; i++) {
        array[i - index] = list[i]
    }

    return array
}

},{}],80:[function(require,module,exports){
(function (global){(function (){

/**
 * Module exports.
 */

module.exports = deprecate;

/**
 * Mark that a method should not be used.
 * Returns a modified function which warns once by default.
 *
 * If `localStorage.noDeprecation = true` is set, then it is a no-op.
 *
 * If `localStorage.throwDeprecation = true` is set, then deprecated functions
 * will throw an Error when invoked.
 *
 * If `localStorage.traceDeprecation = true` is set, then deprecated functions
 * will invoke `console.trace()` instead of `console.error()`.
 *
 * @param {Function} fn - the function to deprecate
 * @param {String} msg - the string to print to the console when `fn` is invoked
 * @returns {Function} a new "deprecated" version of `fn`
 * @api public
 */

function deprecate (fn, msg) {
  if (config('noDeprecation')) {
    return fn;
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      if (config('throwDeprecation')) {
        throw new Error(msg);
      } else if (config('traceDeprecation')) {
        console.trace(msg);
      } else {
        console.warn(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
}

/**
 * Checks `localStorage` for boolean values for the given `name`.
 *
 * @param {String} name
 * @returns {Boolean}
 * @api private
 */

function config (name) {
  // accessing global.localStorage can trigger a DOMException in sandboxed iframes
  try {
    if (!global.localStorage) return false;
  } catch (_) {
    return false;
  }
  var val = global.localStorage[name];
  if (null == val) return false;
  return String(val).toLowerCase() === 'true';
}

}).call(this)}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],81:[function(require,module,exports){
'use strict';

var alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_'.split('')
  , length = 64
  , map = {}
  , seed = 0
  , i = 0
  , prev;

/**
 * Return a string representing the specified number.
 *
 * @param {Number} num The number to convert.
 * @returns {String} The string representation of the number.
 * @api public
 */
function encode(num) {
  var encoded = '';

  do {
    encoded = alphabet[num % length] + encoded;
    num = Math.floor(num / length);
  } while (num > 0);

  return encoded;
}

/**
 * Return the integer value specified by the given string.
 *
 * @param {String} str The string to convert.
 * @returns {Number} The integer value represented by the string.
 * @api public
 */
function decode(str) {
  var decoded = 0;

  for (i = 0; i < str.length; i++) {
    decoded = decoded * length + map[str.charAt(i)];
  }

  return decoded;
}

/**
 * Yeast: A tiny growing id generator.
 *
 * @returns {String} A unique id.
 * @api public
 */
function yeast() {
  var now = encode(+new Date());

  if (now !== prev) return seed = 0, prev = now;
  return now +'.'+ encode(seed++);
}

//
// Map each character to its index.
//
for (; i < length; i++) map[alphabet[i]] = i;

//
// Expose the `yeast`, `encode` and `decode` functions.
//
yeast.encode = encode;
yeast.decode = decode;
module.exports = yeast;

},{}]},{},[1]);