How to dynamically change the period/delay of an interval for Angular / RxJS

user_19536760 0
Viewed 81

I want to dynamically change the period/delay of an interval, but unfortunately I am not too familiar with Angular, so I am stuck at this part.

Here is my current code:

timeDiffs : number[] = [] <== this is a preprocessed array with the timemeasurements in milliseconds

this.interval$ = interval(this.timeDiffs[this.intervalCounter++]).subscribe(() => {
    //some function calling here
     this.intervalCounter++; // next index for next iteration with a different time
})
subscribe rxjs angular typescript intervals
2 Answers

You should be able to do this with just concatMap() and timer(). concatMap() guarantee the delays are invoked in correct order only when the previous one completes. timer() will emit once and complete after set delay.

import { from, concatMap, timer } from 'rxjs';

const timeDiffs = [1000, 1000, 3000, 1000];

from(timeDiffs)
  .pipe(
    concatMap(delay => timer(delay)),
  )
  .subscribe(console.log)

Demo: https://stackblitz.com/edit/rxjs-nqyxqk?devtoolsheight=60&file=index.ts

user_3107260

Use BehaviorSubject

const variable$ = new BehaviorSubject(1); //you can set initial value as per your need


this.variable$.pipe(
  switchMap(val => interval(125 * val),
  //now apply your various operators chain as per your need
  takeWhile(),...
  tap(),...
  map()...
).subscribe();

 this.variable$.next(newValue); //you can use this line to change variable  with a new value
user_149855360
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