useState.jsx

import React, { useState } from 'react';

function App() {
  const [ score, setScore ] = useState(0);
  const [ message, setMessage ] = useState('Welcome!');
  
  return (
    <div className="App">
      <header className="App-header">
        <h1>{ message }</h1>
        <h2>{ score }</h2>
        <button onClick={() => setScore(score + 1)}>
          Increase score
        </button>
      </header>
     </div>
    )
};

export default App;