> For the complete documentation index, see [llms.txt](https://lodash.shujuwajue.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lodash.shujuwajue.com/lang/isnil.md).

# \_.isNil（是否是null或者undefined）

**语法：**

```javascript
_.isNil(value)
```

**源代码链接：**[source](https://github.com/lodash/lodash/blob/4.17.10/lodash.js#L11972)

**npm包链接：**[npm package](https://www.npmjs.com/package/lodash.isnil)

**描述：**

检查`value`是否是`null`或者`undefined`。

**开始版本：**4.0.0

**参数：**

* `value (*)`: 要检查的值。

**返回值：**

* `(boolean)`: 如果`value`为`null`或`undefined`，那么返回`true`，否则返回`false`。

**例子：**

```javascript
_.isNil(null);
// => true

_.isNil(void 0);
// => true

_.isNil(NaN);
// => false
```