mishoo/UglifyJS — Issue #253: Some optimization for Undefined
Author: stereobooster
Created: 2011-11-20 19:42:41+00:00
State: open

```javascript
function k(a) {
typeof a ==="undefined";
}
```
should be transformed to

```javascript
function k(a){typeof a==void 0}
```

Additionaly `undefined` and `null` can be compared with `==` it is not obligatory to use `===`