six/lib/es6.js

JavaScript you can bet on.

if (typeof exports === 'object' && typeof define !== 'function') {
  var define = function (factory) {
    factory(require, exports);
  };
}
define(function (require, exports) {
  "use strict";
  global.StopIteration = {};
  Object.defineProperties(global.Object, {
    define: {
      value: function (target, source) {
        var desc = {};
        Object.keys(source).forEach(function (key) {
          return desc[key] = Object.getOwnPropertyDescriptor(source, key);
        }.bind(this));
        Object.defineProperties(target, desc);
        return target;
      },
      enumerable: false,
      writable: true,
      configurable: true
    }
  });
  Array.prototype.iterator = function () {
    return {
      elements: this,
      index: 0,
      next: function () {
        if (this.index >= this.elements.length)
          throw StopIteration;
        return this.elements[this.index++];
      }
    };
  };
});