How to create a one minute reverse timer

Ionic Framework ionic-v3
1

Am trying to add a 1 minute reverse timer to verify OTP.

 let timer = TimerObservable.create(1000, 1000).subscribe(t => { this.tick = t; });

Using this , it increments in ascending order. I need this to be like 1:59,1:58,1:57 …

2

You can do something like this:

Observable.timer(0, 1000)
.map(value => 60 - value)
.takeWhile(value => value > 0)
.subscribe(t => this.tick = t);
3

Thanks … This fixed the issue