uuid.js

/**
 * Fast UUID generator, RFC4122 version 4 compliant.
 * @author Jeff Ward (jcward.com).
 * @license MIT license
 * @link http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/21963136#21963136
 **/
var UUID = (function () {
  'use strict';
  var self = {};
  var lut = [];

  for(var i = 0; i < 256; i++) {
    lut[i] = (i < 16 ? '0' : '') + (i).toString(16);
  }

  /**
   * Generates a UUID
   * @returns {string}
   */
  self.generate = function () {
    var d0 = Math.random() * 0xffffffff | 0;
    var d1 = Math.random() * 0xffffffff | 0;
    var d2 = Math.random() * 0xffffffff | 0;
    var d3 = Math.random() * 0xffffffff | 0;
    return lut[d0 & 0xff] + lut[d0 >> 8 & 0xff] + lut[d0 >> 16 & 0xff] + lut[d0 >> 24 & 0xff] + '-' +
      lut[d1 & 0xff] + lut[d1 >> 8 & 0xff] + '-' + lut[d1 >> 16 & 0x0f | 0x40] + lut[d1 >> 24 & 0xff] + '-' +
      lut[d2 & 0x3f | 0x80] + lut[d2 >> 8 & 0xff] + '-' + lut[d2 >> 16 & 0xff] + lut[d2 >> 24 & 0xff] +
      lut[d3 & 0xff] + lut[d3 >> 8 & 0xff] + lut[d3 >> 16 & 0xff] + lut[d3 >> 24 & 0xff];
  };
  return self;

})();