isDate.js

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = isDate;

var _assertString = require('./util/assertString');

var _assertString2 = _interopRequireDefault(_assertString);

var _isISO = require('./isISO8601');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function getTimezoneOffset(str) {
  var iso8601Parts = str.match(_isISO.iso8601);
  var timezone = void 0,
      sign = void 0,
      hours = void 0,
      minutes = void 0;
  if (!iso8601Parts) {
    str = str.toLowerCase();
    timezone = str.match(/(?:\s|gmt\s*)(-|\+)(\d{1,4})(\s|$)/);
    if (!timezone) {
      return str.indexOf('gmt') !== -1 ? 0 : null;
    }
    sign = timezone[1];
    var offset = timezone[2];
    if (offset.length === 3) {
      offset = '0' + offset;
    }
    if (offset.length <= 2) {
      hours = 0;
      minutes = parseInt(offset, 10);
    } else {
      hours = parseInt(offset.slice(0, 2), 10);
      minutes = parseInt(offset.slice(2, 4), 10);
    }
  } else {
    timezone = iso8601Parts[21];
    if (!timezone) {
      // if no hour/minute was provided, the date is GMT
      return !iso8601Parts[12] ? 0 : null;
    }
    if (timezone === 'z' || timezone === 'Z') {
      return 0;
    }
    sign = iso8601Parts[22];
    if (timezone.indexOf(':') !== -1) {
      hours = parseInt(iso8601Parts[23], 10);
      minutes = parseInt(iso8601Parts[24], 10);
    } else {
      hours = 0;
      minutes = parseInt(iso8601Parts[23], 10);
    }
  }
  return (hours * 60 + minutes) * (sign === '-' ? 1 : -1);
}

function isDate(str) {
  (0, _assertString2.default)(str);
  var normalizedDate = new Date(Date.parse(str));
  if (isNaN(normalizedDate)) {
    return false;
  }

  // normalizedDate is in the user's timezone. Apply the input
  // timezone offset to the date so that the year and day match
  // the input
  var timezoneOffset = getTimezoneOffset(str);
  if (timezoneOffset !== null) {
    var timezoneDifference = normalizedDate.getTimezoneOffset() - timezoneOffset;
    normalizedDate = new Date(normalizedDate.getTime() + 60000 * timezoneDifference);
  }

  var day = String(normalizedDate.getDate());
  var dayOrYear = void 0,
      dayOrYearMatches = void 0,
      year = void 0;
  // check for valid double digits that could be late days
  // check for all matches since a string like '12/23' is a valid date
  // ignore everything with nearby colons
  dayOrYearMatches = str.match(/(^|[^:\d])[23]\d([^T:\d]|$)/g);
  if (!dayOrYearMatches) {
    return true;
  }
  dayOrYear = dayOrYearMatches.map(function (digitString) {
    return digitString.match(/\d+/g)[0];
  }).join('/');

  year = String(normalizedDate.getFullYear()).slice(-2);
  if (dayOrYear === day || dayOrYear === year) {
    return true;
  } else if (dayOrYear === '' + day / year || dayOrYear === '' + year / day) {
    return true;
  }
  return false;
}
module.exports = exports['default'];