react-use/docs/useUnmount.md

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

import {useUnmount} from 'react-use';

const Demo = () => {
  useUnmount(() => alert('UNMOUNTED'));
  return null;
};

Reference

useUnmount(fn: () => void | undefined);