State with useState

TODO i18n: Full body translation pending. Title and description are localized; the body below remains in Portuguese for now.

useState guarda um valor entre renders e agenda uma atualização da UI quando muda.

import { useState } from 'react';

function App() {
  const [count, setCount] = useState(0);
  return (
    <button type="button" onClick={() => setCount((c) => c + 1)}>
      Cliques: {count}
    </button>
  );
}

HTML shell note: each click updates state → React re-renders App inside the playground #root. The outer document (import map, Sucrase, createRoot) stays the same.