Observable forkJoin not firing

Question

I'm trying to use forkJoin on two Observables. One of them starts as a stream... If I subscribe to them directly I get a response, forkJoin isn't firing though. Any ideas?

private data$: Observable<any[]>; private statuses$: Observable<any[]>; private queryStream = new Subject<string>();      ....  this.data$ = this.queryStream     .startWith('')      .flatMap(queryInput => {             this.query = queryInput             return this._companyService.getCompanies(this.queryRequired + ' ' + this.query, this.page, this.sort);                 })             .share();      ...  Observable.forkJoin(this.statuses$, this.companies$)             .subscribe(res => {                 console.log('forkjoin');                 this._countStatus(res[0], res[1]);             });   // This shows arrays in the console...  this.statuses$.subscribe(res => console.log(res)); this.companies$.subscribe(res => console.log(res));  // In the console Array[9] Array[6] 

Answer 1

forkJoin emits only when all inner observables have completed. If you need an equivalent of forkJoin that just listens to a single emission from each source, use combineLatest + take(1)

combineLatest(   this.statuses$,   this.companies$, ) .pipe(   take(1), ) .subscribe(([statuses, companies]) => {   console.log('forkjoin');   this._countStatus(statuses, companies); }); 

As soon as both sources emit, combineLatest will emit and take(1) will unsubscribe immediately after that.