# `useUnmount` React lifecycle hook that calls a function when the component will unmount. Use `useLifecycles` if you need both a mount and unmount function. ## Usage ```jsx import {useUnmount} from 'react-use'; const Demo = () => { useUnmount(() => alert('UNMOUNTED')); return null; }; ``` ## Reference ```ts useUnmount(fn: () => void | undefined); ```