text: function DeltaTimer() {
  
    this.start = null
    this.before = null
    this.current = null
    this.paused = false
    this.delta = 0
  
  }
  
  DeltaTimer.prototype.init = function () {
    this.start = performance.now()
    this.before = performance.now()
    this.current = performance.now()
  }
  
  /**
   * @description
   * Update tick time. It's returns interval of tick time with before.
   * 
   * @returns {Number}
   */
  DeltaTimer.prototype.update = function () {
  
    this.before = this.current
    this.current = performance.now()
    this.delta += this.current - this.before
  
    return this.delta
  
  }
  
  DeltaTimer.prototype.uptime = function () {
    return this.current - this.start
  }
  
  DeltaTimer.prototype.clear = function () {
    this.delta = 0
  }
  
  DeltaTimer.prototype.pause = function () {
    this.paused = true
  }
  
  DeltaTimer.prototype.play = function () {
    this.paused = false
  }
  
  DeltaTimer.prototype.check = function (fps) {
  
    return ~~this.delta >= ~~(1000 / fps) - 1
  
  }
  
  DeltaTimer.prototype.checkAndClear = function (fps) {
  
    let r
  
    if (r = this.check(fps)) {
      this.clear()
    }
  
    return r
  
  }
  
  
  export default DeltaTimer