const root = ReactDOM.createRoot(document.getElementById('root'));
function Clock(props) {
return (
<div>
<h1>Hello, world!</h1>
<h2>It is {props.date.toLocaleTimeString()}.</h2>
</div>
);
}
function tick() {
root.render(<Clock date={new Date()} />);
}
setInterval(tick, 1000);