> For the complete documentation index, see [llms.txt](https://mm.ricky.moe/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mm.ricky.moe/javascript/js-kai-fa-zhi-shi-dian/kong-zhi-pan-duan.md).

# 空值判断

## 空数组判断

通过上面的类型判断是数组类型，然后它的`length = 0`即可

## 空对象判断

### Object.keys() 的长度为 0

```javascript
var obj = {}
Object.keys(obj).length === 0 // true
```

### 对象转字符串为 {}

```javascript
var obj = {}
var a = JSON.stringify(obj)
a === "{}" // true
```

### Object.getOwnPropertyNames() 长度为空

```javascript
var obj = {}
Object.getOwnPropertyNames(obj).length === 0; // true
```