nested.js

function App({ date }) {
  const [currentDate, setCurrentDate] = useState(new Date());
  const [count, setCount] = useState(0);

  function updateCount(byValue) {
    setCount(count + byValue);
    setCurrentDate(new Date());
  }

  function formatDate() {
    const hour = date.getHours();
    const minute = date.getMinutes();
    const second = date.getSeconds();

    return (`${hour}:${minute}:${second}`);
  }

  const prettyDate = formatDate();

  return (
    <div className="App">
      <h1>Hello CodeSandbox</h1>
      <h2>
        You clicked {count} times, last time at {prettyDate}!
      </h2>

      <button onClick={() => updateCount(-1)}>Decrement</button>
      <button onClick={() => updateCount(1)}>Increment</button>
    </div>
  );
}