class HelloWorld extends React.Component<{date: Date}, void> {

render() {
  return (
    <p>
      Hello, <input type="text" placeholder="Your name here" />!
      It is {this.props.date.toTimeString()}
    </p>
  );
}

}

setInterval(function() {

ReactDOM.render(
  <HelloWorld date={new Date()} />,
  document.getElementById('example')
);

}, 500);