Hello World <div></div> function Button() { const [yesNo, setYesNo] = React.useState('Yes'); return ( { setYesNo(yesNo === 'Yes' ? 'No' : 'Yes') }} style={{ fontSize: '3rem', padding: '1rem', width: '10rem' }} > {yesNo} ); } function App({children}) { return ( <div> <div> {children} </div> </div> ); } ReactDOM.render( , document.getElementById('root') );