http://wingolog.org/archives/2013/05/08/generators-in-v8

 // notice: function* instead of function
function* values() {
  for (var i = 0; i < arguments.length; i++) {
    yield arguments[i];
  }
}

var o = values(1, 2, 3);  // => [object Generator]

加上以后 Node.js 就不是原来的异步了啊...