## isUndefined + [link](./isUndefined "Link to this entry.") + [source](https://github.com/lodash/lodash/blob/4.5.0正式版/lodash.src.js#L10351 "View in source.") + [npm](https://www.npmjs.com/package/lodash.isundefined "See the npm package.") ``` _.isUndefined(value) ``` 检查 `value` 是否是 `undefined`. ### 参数 1. value (\*) 要检查的值 ### 返回值 (boolean) 如果是正确的类型，返回 `true`，否则返回 `false` ### 示例 ``` _.isUndefined(void 0); // => true _.isUndefined(null); // => false ```