55 lines
1.5 KiB
Markdown
55 lines
1.5 KiB
Markdown
---
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title: React usePortal hook
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tags: hooks,state,effect
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expertise: advanced
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author: chalarangelo
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cover: blog_images/interior-3.jpg
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firstSeen: 2022-01-05T05:00:00-04:00
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---
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Creates a portal, allowing rendering of children outside the parent component.
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- Use the `useState()` hook to create a state varible that holds the `render()` and `remove()` functions for the portal.
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- Use `ReactDOM.createPortal()` and `ReactDOM.unmountComponentAtNode()` to create a portal and a function to remove it. Use the `useCallback()` hook to wrap and memoize these functions as `createPortal()`.
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- Use the `useEffect()` hook to call `createPortal()` and update the state variable any time `el`'s value changes.
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- Finally, return the `render()` function of the state variable.
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```jsx
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const usePortal = el => {
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const [portal, setPortal] = React.useState({
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render: () => null,
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remove: () => null,
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});
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const createPortal = React.useCallback(el => {
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const Portal = ({ children }) => ReactDOM.createPortal(children, el);
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const remove = () => ReactDOM.unmountComponentAtNode(el);
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return { render: Portal, remove };
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}, []);
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React.useEffect(() => {
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if (el) portal.remove();
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const newPortal = createPortal(el);
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setPortal(newPortal);
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return () => newPortal.remove(el);
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}, [el]);
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return portal.render;
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};
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```
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```jsx
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const App = () => {
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const Portal = usePortal(document.querySelector('title'));
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return (
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<p>
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Hello world!
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<Portal>Portalized Title</Portal>
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</p>
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);
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};
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ReactDOM.render(<App />, document.getElementById('root'));
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```
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