import {useState} from 'react';
import useMounted from 'react-use-mounted';

function MyComponent () {

  const [foo, setFoo] = useState ( false );
  const mounted = useMounted ();

  useWhatever ( () => {
    if ( !mounted.current ) return; // Not mounted, avoiding calling `setFoo`
    setFoo ( true );
  });

}