moment-clock.jsx

import React, { Component } from 'react';
import moment from 'moment';

class Clock extends Component {
  constructor() {
    super()
    this.state = {
      formattedDateTime: moment().format('MMMM Do YYYY, h:mm:ss a'),
    };
  }

  tick() {
    this.setState({
      formattedDateTime: moment().format('MMMM Do YYYY, h:mm:ss a'),
    });
  }

  render() {
    setTimeout(this.tick.bind(this), 0);

    return (
      <div className="clock">
        {this.state.formattedDateTime}
      </div>
    )
  }
}

export default Clock;