Clock.class.jsx

class Clock extends Component {
  constructor(props) {
    super(props);
    this.state = {
      time: new Date().toLocaleTimeString(),
    };
  }
  componentDidMount() {
    setInterval(() => {
      this.setState({ time: new Date().toLocaleTimeString() });
    }, 1000);
  }
  render() {
    const { className, style } = this.props;
    const { time } = this.state;
    return (
      <span
        className={clsx('Clock', className)}
        style={style}
      >
        {time}
      </span>
    );
  }
}