code: function (items) {
          this.items = [];
  	this.bindings = {};
          this.length = 0;
          this.type = "set";
          if (items) {
              for (var i = 0, ii = items.length; i < ii; i++) {
                  if (items[i]) {
                      this[this.items.length] = this.items[this.items.length] = items[i];
                      this.length++;
                  }
              }
          }
      }
docs: Set