code: function _assign (target, source) {
    var s, from, key;
    var to = Object(target);
    for (s = 1; s < arguments.length; s++) {
      from = Object(arguments[s]);
      for (key in from) {
        if (own(from, key)) {
          to[key] = from[key];
        }
      }
    }
    return to
  }
docs: Object.assgin polyfill