Stopwatch Resume and Stop

stopwatch.js

  resume = () => {
    //update the timestart to continue with same time
    this.setState(state => {
      let timestart = moment().unix() - (this.state.timestop - this.state.timestart)

      return {running: true, timestart}
    }, () => {
      this.startTimer()
    })
  }

  stop = () => { //Press STOP
    clearInterval(this.timer) //Release the timer

    this.setState({
      running: false,
      timestop: moment().unix()
    })
  }