code: function buildDontEnumFix() {
    if (!({toString:1}).propertyIsEnumerable('toString')) {
      var forEachEnumerableProperty = forEachProperty;
      forEachProperty = function(obj, fn) {
        forEachEnumerableProperty(obj, fn);
        for (var i = 0, key; key = DONT_ENUM_PROPS[i]; i++) {
          if (hasOwn(obj, key)) {
            if(fn.call(obj, obj[key], key, obj) === false) break;
          }
        }
      };
    }
  }
docs: *
  @fix
  @short Fixes DontEnum bug for iteration methods in < IE9.
  *