$ npm install react-moment-countdown --save

   import React from 'react';
   import ReactMomentCountDown from 'react-moment-countdown';

   export default function CountDownComponent () {
     const dateInFuture = new Date('2017-12-31');

     return (
       <ReactMomentCountDown toDate={dateInFuture} />
     );
   };

import React from 'react';
import ReactMomentCountDown from 'react-moment-countdown';
import moment from 'moment';

export default function CountDownComponent () {
  const dateInFuture = moment('2017-12-31', 'YYYY-MM-DD');

  return (
    <ReactMomentCountDown toDate={dateInFuture} />
  );
};

import {render} from 'react-dom'
import ReactMomentCountDown from 'react-moment-countdown'

render(
  <ReactMomentCountDown toDate='2017-12-31 23:59:59' sourceFormatMask='YYYY-MM-DD HH:mm:ss' />,
  document.getElementById('sample-date')
)

import {render} from 'react-dom'
import ReactMomentCountDown from 'react-moment-countdown'
import moment from 'moment'

const sampleDate = moment('2017-12-31')

render(
  <ReactMomentCountDown toDate={sampleDate} targetFormatMask='DD:HH:mm:ss' />,
  document.getElementById('sample-date')
)

import React, {PureComponent} from 'react'
import ReactMomentCountDown from 'react-moment-countdown'
import moment from 'moment'

export default class SampleClass extends PureComponent {
  constructor (props) {
    super(props)
    this.state = { endCountdown: false }
    this.sampleOnTick = this.sampleOnTick.bind(this)
    this.sampleOnCountdownEnd = this.sampleOnCountdownEnd.bind(this)
  }
  sampleOnTick (countdown) {
    this.setState({ endCountdown: countdown <= 0 })
  }
  sampleOnCountdownEnd () {
    console.log('Happy Birthday to you :)')
  }
  render () {
    const dateInFuture = moment('2017-12-31', 'YYYY-MM-DD');
    return (
      <ReactMomentCountDown toDate={dateInFuture}
        onTick={this.sampleOnTick}
        onCountdownEnd={this.sampleOnCountdownEnd} />
    )
  }
}