enzyme/docs/api/ReactWrapper/update.md

JavaScript Testing utilities for React

# `.update() => Self`

Forces a re-render. Useful to run before checking the render output if something external
may be updating the state of the component somewhere.

NOTE: can only be called on a wrapper instance that is also the root instance.


#### Returns

`ReactWrapper`: Returns itself.



#### Example

```jsx
class ImpureRender extends React.Component {
  constructor(props) {
    super(props);
    this.count = 0;
  }
  render() {
    this.count += 1;
    return <div>{this.count}</div>;
  }
}
```
```jsx
const wrapper = mount(<ImpureRender />);
expect(wrapper.text()).to.equal('0');
wrapper.update();
expect(wrapper.text()).to.equal('1');
```