Using the for loop to make multiple HTTP requests, and then subscribe to all of them separately should be avoided in order not to have many Observable connections opened. As @Juan Mendes mentioned, Observable.forkJoin will return an array of tasks that match the index of each process in your processes array. You can also assign … Read more
The flatMap operator allows to do that. I don’t fully understand what you try to do but I’ll try to provide an answer… If you want load all the getPostsPerUser() { return this.http.get(“https://stackoverflow.com/users”) .map(res => res.json()) .flatMap((result : Array<User>) => { return Observable.forkJoin( result.map((user : User) => user.getPosts()); }); } Observable.forkJoin allows you to wait … Read more
You can’t directly return totalQuestions like that, you need to use a subject to achieve that. getTotalQuestions(idForm:string): Observable<string> { let totalQuestions:number; var subject = new Subject<string>(); this.getFirebaseData(idForm+”/Metadatos”) .subscribe(items => { items.map(item => { totalQuestions=item.Total; console.log(totalQuestions); subject.next(totalQuestions); }); } ); return subject.asObservable(); } Usage: getTotalQuestion(idForm).subscribe((r)=>console.log(r))
You can’t return an observable from subscribe but if you use map instead of subscribe then an Observable is returned. canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot):Observable<boolean> { // get route to be activated this.routeToActivate = route.routeConfig.path; // get user access levels return this._firebase.isUserAdminObservable .map(user => { // do something here // user.access_level; return true; }) .first(); // … Read more
You can use the | async pipe: <div *ngIf=”(list$ | async)?.length==0″>No records found.</div> Update – 2021-2-17 <ul *ngIf=”(list$| async) as list; else loading”> <li *ngFor=”let listItem of list”> {{ listItem.text }} </li> </ul> <ng-template #loading> <p>Shows when no data, waiting for Api</p> <loading-component></loading-component> </ng-template> Update – Angular Version 6: If you are loading up a … Read more
Perhaps you could try to use the of method of the Observable class: import { Observable } from ‘rxjs/Observable’; import ‘rxjs/add/observable/of’; public fetchModel(uuid: string = undefined): Observable<string> { if(!uuid) { return Observable.of(new TestModel()).map(o => JSON.stringify(o)); } else { return this.http.get(“http://localhost:8080/myapp/api/model/” + uuid) .map(res => res.text()); } }
Provided it is a typo and the second element has subItems as well (and not searchProfiles), you don’t need flatMap or any thing of the sort, you can do it in a plain map using js array operators: var transformed = [].concat(…result.map(item => item.subItems)); or in your case httpResult$.map(result => [].concat(…result.map(item => item.subItems)) if the … Read more
Maybe some pictures help? The numbers here indicate the order of operations. Send the Http Request Component is initialized and calls the getMovies method of the movieService. The movieService getMovies method returns an Observable. NOT the data at this point. The component calls subscribe on the returned Observable. The get request is submitted to the … Read more
Try to use combineLatest instead of forkJoin : With combineLatest : const combined = Observable.combineLatest( this.http.get(‘https://testdb1.firebaseio.com/.json’).map((res: Response) => res.json()), this.http.get(‘https://testdb2.firebaseio.com/.json’).map((res: Response) => res.json()) ) combined.subscribe(latestValues => { const [ data_changes , data_all ] = latestValues; console.log( “data_changes” , data_changes); console.log( “data_all” , data_all); }); You can also handle it by forkJoin , but forkJoin will … Read more
To get data from an observable, you need to subscribe: this.singleEvents$.subscribe(event => this.event = event); In the template you can directly bind to observables using the async pipe: {{singleEvents$ | async}}