gistfile1.txt

const App = () => {
  const [num, setNum] = useState(1);
  useEffect(() => {
    document.addEventListener("click", (ev) => {
      setNum(Math.random());
    });
    return function cleanup() {
      document.removeEventListener("click", (ev) => {});
    };
  }, [num]);
  console.log("render");
  return (
    <div className="App">
      <header className="App-header">{num}</header>
    </div>
  );
};

export default App;