How to make one Observable sequence wait for another to complete before emitting?

by

A couple ways I can think of

import {take, publish} from 'rxjs/operators'
import {concat} from 'rxjs'

//Method one

var one = someObservable.pipe(take(1));
var two = someOtherObservable.pipe(take(1));
concat(one, two).subscribe(function() {/*do something */});

//Method two, if they need to be separate for some reason
var one = someObservable.pipe(take(1));
var two = someOtherObservable.pipe(take(1), publish());
two.subscribe(function(){/*do something */});
one.subscribe(function(){/*do something */}, null, two.connect.bind(two));

More Related Contents:

  1. Promise.all behavior with RxJS Observables?
  2. Rxjs One Observable Feeding into Another
  3. What are use cases for mergeMap operator?
  4. Is it good to call subscribe inside subscribe?
  5. Return an empty Observable
  6. Angular 7 go offline?
  7. How do I return the response from an Observable/http/async call in angular?
  8. Hot and Cold observables: are there ‘hot’ and ‘cold’ operators?
  9. How to get current value of RxJS Subject or Observable?
  10. Angular 4 Interceptor retry requests after token refresh
  11. Why do we need to use flatMap?
  12. How can I close a dropdown on click outside?
  13. What is “callback hell” and how and why does RX solve it?
  14. How can I `await` on an Rx Observable?
  15. What are the semantics of different RxJS subjects?
  16. Subject vs BehaviorSubject vs ReplaySubject in Angular
  17. Chaining Observables in RxJS
  18. How to do the chain sequence in rxjs
  19. Is it a good practice using Observable with async/await?
  20. RxJS sequence equivalent to promise.then()?
  21. RXJS Wait for all observables in an array to complete (or error)
  22. How to achieve a debounce service on input keyup event in angular2 with rxjs
  23. How to cancel a subscription in Angular2
  24. How to ‘wait’ for two observables in RxJS
  25. What is the difference between BehaviorSubject and Observable?
  26. Upgrading to Angular 10 – Fix CommonJS or AMD dependencies can cause optimization bailouts
  27. How to catch error and continue executing a sequence in RxJs?
  28. How to implement a global loader in Angular
  29. Observable.forkJoin with a for loop
  30. Observable Finally on Subscribe

Leave a Comment