src/components/controls/DatePicker/Clock.jsx

import React from 'react';
import moment from 'moment';
import PropTypes from 'prop-types';

/**
 * Компонент Clock
 * @reactProps {function} onClick - событие клика
 */
class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      time: moment(),
    };
  }

  componentDidMount() {
    setInterval(() => {
      this.setState({ time: moment() });
    });
  }

  render() {
    return (
      <div className="n2o-calendar-clock" onClick={this.props.onClick}>
        {this.state.time.format('H:mm:ss')}
      </div>
    );
  }
}

Clock.propTypes = {
  onClick: PropTypes.func,
};

export default Clock;