The same service instance isn’t being shared across your App and Home components because you have listed SidenavService as a provider for both. When you define service provider in the providers entry of a Component decorator, that service is then available to that component and all of its children as a singleton, meaning the same … Read more
You need to import the Observable class this way to be able to use the interval method: import {Observable} from ‘rxjs/Rx’; or import {Observable} from ‘rxjs/Observable’; import ‘rxjs/add/observable/interval’;
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 }); }
Here is a simple visual to see the difference: As seen above … an Observable is a stream of events or data. They are often returned from Angular methods, such as the http.get and the myinputBox.valueChanges. Subscribing “kicks off” the observable stream. Without a subscribe (or an async pipe) the stream won’t start emitting values. … Read more
The .subscribe() function is similar to the Promise.then(), .catch() and .finally() methods in jQuery, but instead of dealing with promises it deals with Observables. That means it will subscribe itself to the observable of interest (which is getTasks() in your case) and wait until it is successful and then execute the first passed callback function … Read more
The subscribe() call returns a Subscription and this is what you use to unsubscribe: class JobToolbarComponent private subscr:Subscription; ngOnInit() { … this.subscr = this.form.valueChanges … … } ngOnDestroy() { this.subscr.unsubscribe(); } }
Use iif rxjs. iif accepts a condition function and two Observables. When an Observable returned by the operator is subscribed, condition function will be called. https://www.learnrxjs.io/operators/conditional/iif
Make a copy of object using the Object.assign method and try again, this.collectionPages = Object.assign([], this.collectionPages); this.collectionPages.push(collectionPageDbModel); ES6 simplified code would be, this.collectionPages = […this.collectionPages, collectionPageDbModel]
So the answer is no, you don’t. Ng2 will clean it up itself. The Http service source, from Angular’s Http XHR backend source: Notice how it runs the complete() after getting the result. This means it actually unsubscribes on completion. So you don’t need to do it yourself. Here is a test to validate: fetchFilms() … Read more
Disclaimer: I’m the author of the tool I mention below. This can be accomplished by keeping a list where new subscriptions are added to, and removing subscriptions from this list once it is unsubscribed. The troublesome part is observing subscriptions. A straightforward way to achieve this is by monkey-patching the Observable#subscribe() method, that is, replacing … Read more