useKonamiCode

useKonami.js

const code = [
  'ArrowUp', 'ArrowUp', 'ArrowDown', 
  'ArrowDown', 'ArrowLeft', 'ArrowRight', 
  'ArrowLeft', 'ArrowRight', 'KeyB', 'KeyA'
];

const useKonami = () => {
  const [isActive, setActive] = useState(false);

  useEffect(() => {
    let cache = [];

    const handler = (e) => {
      cache = [...cache, e.code].slice(-code.length);
      cache.join() === code.join() && setActive(true);
    }
    document.addEventListener('keydown', handler);
    return () => document.removeEventListener('keydown', handler);
  }, [])

  return isActive;
}