<pre class="shiki github-dark shaku"><code>import { useEffect, useRef } from 'react';export function useIsMounted(): () =&gt; boolean { const isMountedRef = useRef&lt;boolean&gt;(false) useEffect(() =&gt; { isMountedRef.current = true return () =&gt; isMountedRef.current = false }, []) return () =&gt; isMountedRef.current}</code></pre>

Implement useIsMounted to get a isMounted function. (mounted will return true, unmounted will return false)

When we handle async requests in React, we need to pay attention if the component is already unmounted. Please implement useIsMounted() for us to easi…