timer.js

export default class Timer {
  constructor () {
    this._running = false
    this._startTime = null
    this._stopTime = null
  }

  start () {
    if (this._running) {
      return
    }
    this._startTime = new Date()
    this._running = true
  }

  stop () {
    if (!this._running) {
      return
    }
    this._stopTime = new Date()
    this._running = false
  }

  reset () {
    this._running = false
    this._startTime = null
    this._stopTime = null
  }

  getElapsedTime () {
    if (this._startTime === null) {
      return ['0', '0']
    }
    let elapsed = 0
    if (this._stopTime !== null) {
      elapsed = this._stopTime - this._startTime
    }
    else {
      elapsed = new Date() - this._startTime
    }
    let seconds = Math.floor(elapsed / 1000)
    const minutes = Math.floor(seconds / 60)
    return [minutes.toString(), (seconds % 60).toString()]
  }


}