33 lines
814 B
Markdown
33 lines
814 B
Markdown
---
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title: useComponentWillUnmount
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tags: hooks,effect,beginner
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firstSeen: 2020-01-03T16:00:56+02:00
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lastUpdated: 2020-11-16T14:17:53+02:00
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---
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Executes a callback immediately before a component is unmounted and destroyed.
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- Use `useEffect()` with an empty array as the second argument and return the provided callback to be executed only once before cleanup.
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- Behaves like the `componentWillUnmount()` lifecycle method of class components.
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```jsx
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const useComponentWillUnmount = onUnmountHandler => {
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React.useEffect(
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() => () => {
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onUnmountHandler();
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},
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[]
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);
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};
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```
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```jsx
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const Unmounter = () => {
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useComponentWillUnmount(() => console.log('Component will unmount'));
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return <div>Check the console!</div>;
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};
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ReactDOM.render(<Unmounter />, document.getElementById('root'));
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```
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