import { useState, useEffect } from "react";
import ReactDOM from "react-dom/client";
function Timer() {
  const [count, setCount] = useState(0);
  useEffect(() => {
    let timer = setTimeout(() => {
    setCount((count) => count + 1);
  }, 1000);
  return () => clearTimeout(timer)
  }, []);
  return <h1>I've rendered {count} times!</h1>;
}
const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<Timer />);
/*
Note: To clear the timer, we had to name it.
*/