type definitions, faster queue, rename pop to shift

README.md

@@ -3,8 +3,7 @@
   a simple asynchronous queue
 
 [![Build Status](https://img.shields.io/travis/then/queue/master.svg)](https://travis-ci.org/then/queue)
-[![Dependency Status](https://img.shields.io/gemnasium/then/queue.svg)](https://gemnasium.com/then/queue)
-[![NPM version](https://img.shields.io/npm/v/then-queue.svg)](http://badge.fury.io/js/then-queue)
+[![NPM version](https://img.shields.io/npm/v/then-queue.svg)](https://www.npmjs.com/package/then-queue)
 
 ## Installation
 
@@ -25,14 +24,10 @@ var q = new Queue();
 
   Push an item onto the queue
 
-### queue.pop() -> Promise Item
+### queue.shift() -> Promise Item
 
-  Pop an item from the queue
+  Remove an item from the queue
 
 ### queue.length
 
-  Amount of items in the queue (note that this can be negative if `pop` has been called more times than `push`).
-
-### Events
-
-The `length-changed` event gets emitted whenever `pop` or `push` has been called. You could use it to spawn/kill workers when the length changes.
+  Amount of items in the queue (note that this can be negative if `shift` has been called more times than `push`).

index.d.ts

@@ -0,0 +1,6 @@
+declare class ThenQueue<T> {
+  readonly length: number;
+  push(item: T | Promise<T>): void;
+  shift(): Promise<T>
+}
+export default ThenQueue;

index.js

@@ -1,41 +1,61 @@
 'use strict';
 
-var EventEmitter = require('events').EventEmitter
-var Promise = require('promise')
+module.exports = ThenQueue
+module.exports.default = ThenQueue
 
-module.exports = Queue
-function Queue() {
-  if (!(this instanceof Queue)) return new Queue()
-  EventEmitter.call(this)
-  this._items = []
-  this._waiting = []
+function ThenQueue() {
+  if (!(this instanceof ThenQueue)) return new ThenQueue()
+  this._items = new SimpleQueue();
+  this._waiting = new SimpleQueue();
   this.length = 0
 }
-Queue.prototype = Object.create(EventEmitter.prototype)
-Queue.prototype.constructor = Queue
 
-Queue.prototype.push = function(item) {
+ThenQueue.prototype.push = function push(item) {
   this.length++
-  this.emit('length-changed', this.length)
-  if (this._waiting.length) {
-    var waiting = this._waiting.shift()
+
+  var waiting = this._waiting.shift()
+  if (waiting) {
     waiting(item)
   }
   else {
     this._items.push(item)
   }
 }
 
-Queue.prototype.pop = function(cb) { var self = this
+ThenQueue.prototype.shift = function shift() {
   this.length--
-  this.emit('length-changed', this.length)
-  if (this._items.length) {
-    var item = this._items.shift()
-    return Promise.resolve(item).nodeify(cb)
+
+  var item = this._items.shift()
+  if (item) {
+    return Promise.resolve(item)
   }
   else {
-    return new Promise(function(resolve, reject) {
-      self._waiting.push(resolve)
-    }).nodeify(cb)
+    var waiting = this._waiting
+    return new Promise(function(resolve) {
+      waiting.push(resolve)
+    })
+  }
+}
+
+function SimpleQueue() {
+  this._head = [];
+  this._tail = [];
+}
+SimpleQueue.prototype.push = function push(item) {
+  this._tail.push(item);
+}
+SimpleQueue.prototype.shift = function shift() {
+  if (this._head.length !== 0) {
+    return this._head.pop();
+  }
+  if (this._tail.length === 1) {
+    return this._tail.pop();
+  }
+  if (this._tail.length > 1) {
+    var temp = this._tail.reverse()
+    this._tail = this._head
+    this._head = temp
+    return this._head.pop();
   }
+  return undefined;
 }

package.json

@@ -27,4 +27,4 @@
   "scripts": {
     "test": "node test"
   }
-}
+}

test/index.js

@@ -6,60 +6,43 @@ var Queue = require('../')
 
 test('queue', function () {
   var q = new Queue();
-  var length = 0;
   var results = [];
-  q.on('length-changed', function (l) {
-    assert(q.length === l)
-    assert(length !== l)
-    length = l
-  })
   assert(q.length === 0);
   q.push(1);
   assert(q.length === 1);
-  assert(length === 1);
   q.push(2);
   assert(q.length === 2);
-  assert(length === 2);
   q.push(3);
   assert(q.length === 3);
-  assert(length === 3);
-  return q.pop().then(function (n) {
+  return q.shift().then(function (n) {
     assert(n === 1);
     assert(q.length === 2);
-    assert(length === 2);
-    return q.pop();
+    return q.shift();
   }).then(function (n) {
     assert(n === 2);
     assert(q.length === 1);
-    assert(length === 1);
-    return q.pop();
+    return q.shift();
   }).then(function (n) {
     assert(n === 3);
     assert(q.length === 0);
-    assert(length === 0);
-    results.push(q.pop());
+    results.push(q.shift());
     assert(q.length === -1);
-    assert(length === -1);
-    results.push(q.pop());
+    results.push(q.shift());
     assert(q.length === -2);
-    assert(length === -2);
-    results.push(q.pop());
+    results.push(q.shift());
     assert(q.length === -3);
-    assert(length === -3);
     q.push(1);
     assert(q.length === -2);
     return results.shift();
   }).then(function (n) {
     assert(n === 1);
     q.push(2);
     assert(q.length === -1);
-    assert(length === -1);
     return results.shift();
   }).then(function (n) {
     assert(n === 2);
     q.push(3);
     assert(q.length === 0);
-    assert(length === 0);
     return results.shift();
   }).then(function (n) {
     assert(n === 3);