Observable.forkJoin is not working

Question

I've instantiated two Observable objects:

const observable1 = new Observable.create(observer => observer.next(1)); 
const observable2 = new Observable.create(observer => observer.next(2));  
Observable.forkJoin([observable1, observable2]).subscribe(res => console.log(res));

The above forkJoin() is not working even though each of observable.subscribe() is working.

Any thoughts on this?

Thanks

Answer 1

forkJoin waits for all input streams to complete before emitting a resulting value. Since you don't complete observables, it never emits anything. Also, you don't need new with Observable.create and you can import forkJoin directly - no need to use it on Observable. Change your implementation to this:

import { forkJoin } from 'rxjs/observable/forkJoin';
import { Observable } from 'rxjs/Observable';

const observable1 = Observable.create(observer => { observer.next(1); observer.complete() });
const observable2 = Observable.create(observer => { observer.next(2); observer.complete() });

forkJoin([observable1, observable2]).subscribe(res => console.log(res));

For a really great explanation of combination operators, including forkJoin read:

• Learn to combine RxJs sequences with super intuitive interactive diagrams

and here's the link directly to the explanation of forkJoin operator.