Function useHasMounted

This hook can be useful when trying to avoid hydration errors by making sure your app initially returns a default state on the first render that matches what was pre-rendered on the server.

const DemoUseMounted = () => {
const hasMounted = useMounted();
const [count, setCount] = useState(0);
if (hasMounted) setCount(count => count + 1);
return (
<h1>
{count}
</h1>
);
};
  • Returns boolean

    false before mount (including server-side prerendering) and true otherwise.