--- title: React useMediaQuery hook type: snippet language: react tags: [hooks,state,effect] author: chalarangelo cover: clay-pot-horizon dateModified: 2021-10-13T19:29:39+02:00 --- Checks if the current environment matches a given media query and returns the appropriate value. - Check if `Window` and `Window.matchMedia()` exist. Return `whenFalse` if not (e.g. SSR environment or unsupported browser). - Use `Window.matchMedia()` to match the given `query`. Cast its `matches` property to a boolean and store in a state variable, `match`, using the `useState()` hook. - Use the `useEffect()` hook to add a listener for changes and to clean up the listeners after the hook is destroyed. - Return either `whenTrue` or `whenFalse` based on the value of `match`. ```jsx const useMediaQuery = (query, whenTrue, whenFalse) => { if (typeof window === 'undefined' || typeof window.matchMedia === 'undefined') return whenFalse; const mediaQuery = window.matchMedia(query); const [match, setMatch] = React.useState(!!mediaQuery.matches); React.useEffect(() => { const handler = () => setMatch(!!mediaQuery.matches); mediaQuery.addListener(handler); return () => mediaQuery.removeListener(handler); }, []); return match ? whenTrue : whenFalse; }; ``` ```jsx const ResponsiveText = () => { const text = useMediaQuery( '(max-width: 400px)', 'Less than 400px wide', 'More than 400px wide' ); return {text}; }; ReactDOM.createRoot(document.getElementById('root')).render( ); ```