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My tslint gone crazy? It gives warning for every subscribtion I made in whole app. It doesn't matter if I use old or new syntax it still says that subscribe is deprecated... How to write a subscription that will not be deprecated?
That's what was ok till today:
something.subscribe((user: User) => {
this.userProviderService.setUserId(user.userId);
this.proceed = true;
});
I tried new syntax but makes no change:
something.subscribe({
next: (user: User) => {
this.userProviderService.setUserId(user.userId);
this.proceed = true;
},
complete: () => {},
error: () => {}
});
This is exactly what it's saying:
(method) Observable.subscribe(next?: (value: Object) => void, error?: (error: any) => void, complete?: () => void): Subscription (+4 overloads) @deprecated — Use an observer instead of a complete callback
@deprecated — Use an observer instead of an error callback
@deprecated — Use an observer instead of a complete callback
subscribe is deprecated: Use an observer instead of a complete callback (deprecation)tslint(1)
So how do I subscribe to things now?
715
subscribe isn't deprecated, only the variant you're using is deprecated. In the future, subscribe will only take one argument: either the next handler (a function) or an observer object.
Sadly, no. There are at least two cases where you should explicitly subscribe to Observables in components and directives. First is when the Observable makes a change to the outside world. Most commonly, this is done by issuing a POST (or DELETE or PUT) through HTTP, meant to update the backend.
What is an Observer? An Observer is a consumer of values delivered by an Observable. Observers are simply a set of callbacks, one for each type of notification delivered by the Observable: next , error , and complete .
The subscriber function defines how to obtain or generate values or messages to be published. To execute the observable you have created and begin receiving notifications, you call its subscribe() method, passing an observer. This is a JavaScript object that defines the handlers for the notifications you receive.
rxjs - Angular 11 - subscribe is deprecated: Use an observer instead of a complete callback - Stack Overflow I have an Angular application in which errors are beginning to appear in the subscribe that they are deprecated. This is my subscribe: this.route.params.subscribe(params => { this.clienteI...
Additionally, you should really be unsubscribing from this observable. There are two ways to do this. You could store the value of your observer and unsubscribe in your finalize (and ngOnDestroy) OR use takeWhile to unsubscribe all observables if you have many. This is the recommended way to do it from the angular docs.
Subscribe is deprecated: Use an observer instead of an error callback 0 Angular RxJS Subscribe Behavior with Observer object - this in next/error callback 0 Scope issue in next() callback in Observer 3 'subscribe' is deprecated. Use an observer instead of a complete callback
They are used frequently in Angular and are a technique for event handling, asynchronous programming, and handling multiple values. The observer pattern is a software design pattern in which an object, called the subject, maintains a list of its dependents, called observers, and notifies them automatically of state changes.
I just looked up TSLint (v1.3.3) at VS Code extenstions tab. It says:
❗IMPORTANT: TSLint has been deprecated in favor of ESLint.
As I disabled TSLint and installed ESLint, all warnings related to subscribtions dissapeared.
Cheers!
194
To answer your question "So how do I subscribe to things now": https://rxjs-dev.firebaseapp.com/guide/observer This is it. It is easy to use and pretty similar to what has been done before with the small change that it actually now accepts an object (observer) with 3 keys: next, error, complete.
We had the same discussion like 2 days ago at work and altough you can/should use the observer the deprecation seems to be a false alarm. (We thought we had to change ~900 subscribes):
This is an issue created on the rxjs github page regarding this issue: https://github.com/ReactiveX/rxjs/issues/6060
And in it the devs say it is due to a typescript bug: https://github.com/microsoft/TypeScript/issues/43053
This bug already has been fixed 3 days ago, i am not sure though if it is already in the newest release:
https://github.com/microsoft/TypeScript/pull/43165
33
Better way to solve it
myObservable.subscribe({
next: (val) => { ... },
error: (err) => { ... },
complete: () => { ... }
})
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