genify/nej — pull request #8 by cloudcome (2014-07-31 02:14:34+00:00)
Title: 判断是否为 undefined

`util/chain/NodeList.js#43`

```
return (_result === _node || _result === "undefined" || _result === this ||
_result === _e || _result === _v);

// _result === "undefined" => _result === undefined
// 或者此处可省略，传值不会出现 `undefined`
```