You are not calling the getVideos method. You are calling subscribe on the function reference of getVideos and not the returned value. Call subscribe after you call getVideos(): ngOnInit() { this.videoserv.getvideos().subscribe((response) => { this.videos = response }); }
Depending on how that boolean changes you could expose it as an Observable<boolean> on your service, and then subscribe to that stream in your component. Your service would look something like: @Injectable() export class MyBooleanService { myBool$: Observable<boolean>; private boolSubject: Subject<boolean>; constructor() { this.boolSubject = new Subject<boolean>(); this.myBool$ = this.boolSubject.asObservable(); } …some code that emits … Read more
You can use the Injector import { Injector } from ‘@angular/core’ … constructor(private injector: Injector){ if(true) { this.oneService = <OneService>this.injector.get(OneService); } else { this.twoService = <TwoService>this.injector.get(TwoService); } } As @MeirionHughes mentioned this is called the service locator pattern: The technique is an example of the service locator pattern. Avoid this technique unless you genuinely need … Read more
A call to subscribe returns an instance of Disposable, which has a method dispose. Or if you are using RxJS 5, dispose has been renamed to unsubscribe (thanks @EricMartinez). And from the RxJS docs: …when we’re no longer interested in receiving the data as it comes streaming in, we call dispose on our subscription. Store … Read more
Static methods of a class, unlike instance methods, belong to (are visible on) the class itself (not an instance of it). They do not depend on the instance members of a class and will usually take input from the parameters, perform actions on it, and return some result. They act independently. They do make sense … Read more
I do not think you can. http.post (and get, put, delete, etc) returns a cold Observable, i.e. an Observable for which: its underlying producer is created and activated during subscription Source. This means the function represented by the Observable is activated only with the subscribe() method. Convenience methods subscribe too, see implementation details for Observable#toPromise() … Read more
Interaction between components can be indeed achieved using services. You will need to inject the service use for inter-component communication into all the components which will need to use it (all the caller components and the callee method) and make use of the properties of Observables. The shared service can look something like this: import … Read more
providedIn: ‘root’ is the easiest and most efficient way to provide services since Angular 6: The service will be available application wide as a singleton with no need to add it to a module’s providers array (like Angular <= 5). If the service is only used within a lazy loaded module it will be lazy … Read more
Seems like its not possible to use HostListener in a service. UPDATE like Stanislasdrg Reinstate Monica wrote, there’s a more elegant and more angular way using the renderer.. @Injectable() export class MyMouseService implements OnDestroy { private _destroy$ = new Subject(); public onClick$: Observable<Event>; constructor(private rendererFactory2: RendererFactory2) { const renderer = this.rendererFactory2.createRenderer(null, null); this.createOnClickObservable(renderer); } ngOnDestroy() … Read more
If you like the reactive programming style and want to be consistent within your application to always use observables even for single events (instead of streams of events) then use observables. If that doesn’t matter to you, then use toPromise(). One advantage of observables is, that you can cancel the request. See also Angular – … Read more