App.js

const App = () => {
  const [showModal, setShowModal] = useState(false);
  const handleKeyup = e => e.keyCode === 27 && setShowModal(false);
  const toggleModal = () => setShowModal(!showModal);
  useEffect(() => {
    if (showModal) window.addEventListener('keyup', handleKeyup);
    return () => window.removeEventListener('keyup', handleKeyup);
  });
  
  return <div onClick={toggleModal} className="App">
    App - click window
    {showModal && <Modal>
      <Component />
    </Modal>}
  </div>;
}