Hook for listening for unmounting for component

example_unmount_hook.js

import React, { useEffect } from 'react';

const ProfileContainer = () => {

  // generally I prefer this as useEffect with empty args[]
  useEffect(() => {
    fetch('/api/user') // perform any side effects or network requests
    
    
    // you can have return() for this function which will be executed once component will unmount
    return () => {
      console.log('Unmounting ...');
      doYourUnmountProcess();
    }
  }, []); // <-- empty array means 'run once'

  return <div> Hello World </div>;
};