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
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
You should read up on rxjs’s operators a little. Your examples are very verbose and use flatMap and map in a way they’re not supposed to be used. Also your first example can’t work, because you’re not subscribing to the Observable. This will do what you need: ngOnInit() { this.userService.getUser().pipe( tap(u => this.user = u), … Read more
Rxjs v 6.* It got simplified with newer version of rxjs . 1) Operators import {map} from ‘rxjs/operators’; 2) Others import {Observable,of, from } from ‘rxjs’; Instead of chaining we need to pipe . For example Old syntax : source.map().switchMap().subscribe() New Syntax: source.pipe(map(), switchMap()).subscribe() Note: Some operators have a name change due to name collisions … Read more
You can simply mock Observable throw error object like Observable.throw({status: 404})and test error block of observable. const xService = fixture.debugElement.injector.get(SomeService); const mockCall = spyOn(xService, ‘method’).and.returnValue(Observable.throw({status: 404})); Update 2019 : Since some people are lazy to read comment let me put this here : It’s a best practice to use errors for Rxjs import { throwError … Read more
It really comes down to behavior and semantics. With a Subject – a subscriber will only get published values that were emitted after the subscription. Ask yourself, is that what you want? Does the subscriber need to know anything about previous values? If not, then you can use this, otherwise choose one of the others. … Read more
$ suffix (popularized by Cycle.js) is used to indicate that the variable is an Observable. It could make it to the official style guide too but it’s not there yet Read more here : What does the suffixed dollar sign $ mean? Update: Read more about the trailing “$” sign on Angular website here: https://angular.io/guide/rx-library#naming-conventions-for-observables
>= RC.5 The FormsModule needs to be imported to make ngModel available @NgModule({ imports: [BrowserModule /* or CommonModule */, FormsModule, ReactiveFormsModule], … )} class SomeModule {} <= RC.4 In config.js add ‘@angular/forms’: { main: ‘bundles/forms.umd.js’, defaultExtension: ‘js’ }, in main.ts add import {provideForms, disableDeprecatedForms} from ‘@angular/forms’; bootstrap(App, [disableDeprecatedForms(),provideForms()]) Plunker example See also https://angular.io/docs/ts/latest/cookbook/rc4-to-rc5.html
Operators first() and take(1) aren’t the same. The first() operator takes an optional predicate function and emits an error notification when no value matched when the source completed. For example this will emit an error: import { EMPTY, range } from ‘rxjs’; import { first, take } from ‘rxjs/operators’; EMPTY.pipe( first(), ).subscribe(console.log, err => console.log(‘Error’, … Read more