How do I stop Observable.Timer() or Observable.Interval() automatically after certain period of time

Question

public function(id: number) {
    this.periodicCheckTimer = Observable.timer(10000, 5000).subscribe(
        () => {
          let model = this.find(id);
          if (model['isActivated']) {
            this.periodicCheckTimer.unsubscribe();
          }
        });
  }

I want to stop the timer automatically after 5 mins if the condition if(model['isActivated']) is not satisfied. However if the condition satisfies I can stop it manually. Not sure if the manual stop is still correct in this case.

Any suggestions with other timer functions are also appreciated.

score 5 · Accepted Answer · answered Mar 02 '17 at 14:41

5

I didn't test it out, but here's an alternative to your proposal with the stop after 5mn :

function (id: number) {
  // emit a value after 5mn
  const stopTimer$ = Observable.timer(5 * 60 * 1000);

  Observable
    // after 10s, tick every 5s
    .timer(10000, 5000)
    // stop this observable chain if stopTimer$ emits a value
    .takeUntil(stopTimer$)
    // select the model
    .map(_ => this.find(id))
    // do not go further unless the model has a property 'isActivated' truthy
    .filter(model => model['isActivated'])
    // only take one value so we don't need to manually unsubscribe
    .first()
    .subscribe();
}

answered Mar 02 '17 at 14:41

maxime1992

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What if the function find() returned observable? like if I make it this.find(id).subscribe() it calls the function only one time. – Amit Chigadani Mar 02 '17 at 15:17
If `find` returns an observable, use `switchMap` on it so you don't subscribe to it yourself but `switchMap` will for you. – maxime1992 Mar 02 '17 at 15:26
1

Got it! takeUntil() was the function which I was looking for. Thanks!! Appreciated the way you presented your answer. – Amit Chigadani Mar 02 '17 at 15:47
Glad you liked it and that it was helpful :) – maxime1992 Mar 02 '17 at 15:52

How do I stop Observable.Timer() or Observable.Interval() automatically after certain period of time

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