React Playground

import React, { useState } from 'react';

export default function App() {
  const [n, setN] = useState(0);
  return (
    <div style={{ fontFamily: 'system-ui', padding: 24 }}>
      <h1>Hello React 18</h1>
      <p>Count: {n}</p>
      <button onClick={() => setN(n + 1)}>Add one</button>
    </div>
  );
}