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: 3,6
Completed

Jan 2019: Updated for RxJS 6