Observable.forkJoin() doesn't execute
forkJoin() requires all source Observables to emit at least once and to complete.
This following demo completes as expected:
const source = forkJoin( from([1,2,3]), from([9,8,7,6])).subscribe( x => console.log('GOT:', x), err => console.log('Error:', err), () => console.log('Completed'));Live demo: https://stackblitz.com/edit/rxjs-urhkni
GOT: 3,6CompletedJan 2019: Updated for RxJS 6
Just add observer.complete();
Will not work:
observer.next(...)Will work:
observer.next(...);observer.complete();Hope it helps.
I've faced a similar issue: I was creating a list of observables dynamically and I've noticed that forkjoin() never emits nor completes if the list of observables is empty whereas Promise.all() resolves with an empty list :
Observable.forkJoin([]) .subscribe(() => console.log('do something here')); // This is never calledThe workaround I've found is to check the length of the list and to not use this operator when it is empty.
return jobList.length ? Observable.forkJoin(jobList) : Observable.of([]);