CODE EXAMPLE FOR JAVASCRIPT

timer in angular 8

timeLeft: number = 60;
  interval;

startTimer() {
    this.interval = setInterval(() => {
      if(this.timeLeft > 0) {
        this.timeLeft--;
      } else {
        this.timeLeft = 60;
      }
    },1000)
  }

  pauseTimer() {
    clearInterval(this.interval);
  }
    
<button (click)='startTimer()'>Start Timer</button>
<button (click)='pauseTimer()'>Pause</button>

<p>{{timeLeft}} Seconds Left....</p>