useFPS.js

function useFPS() {
  const [fps, setFPS] = useState(0);
  
  useEffect(() => {
    let then = performance.now();
    let frames = 0;
    let req;

    (function loop(now) {
      req = window.requestAnimationFrame(loop);
      frames++;

      if (now - then >= 1000) {
        setFPS(Math.round((frames * 1000) / (now - then)));
        frames = 0;
        then = now;
      }
    })(then);

    return () => window.cancelAnimationFrame(req);
  }, [setFPS]);

  return fps;
}