Unexpected deprecation warning after upgrading to TypeScript v4.2.2 #43053
Description
Bug Report
🔎 Search Terms
RxJS Deprecation Warning TSLint ESLint VSCode Signature Doc Tags DocTags
🕗 Version & Regression Information
Since TypeScript v4.2.2, I get deprecation warnings with RxJS, that I was not getting in TypeScript v4.1.5
I first opened an issue on RxJS (here), but it may be a TypeScript issue
💻 Code
import { Observable, Subject } from 'rxjs';
const somethingHappened: Subject<void> = new Subject();
const somethingHappened$: Observable<void> = somethingHappened.asObservable();
// Deprecation warning on the next line
somethingHappened$.subscribe(() => {
console.log('something happened');
});
somethingHappened.next();🙁 Actual behavior
When I subscribe to the observable, I get the deprecation warning subscribe is deprecated: Use an observer instead of a complete callback even though I'm not using any complete callback
It occurs with both TSLint v6.1.3 and ESLint v7.21.0 (using eslint-plugin-deprecation v1.2.0)
Here are the signatures for the subscribe method in RxJS v6.6.6 :
subscribe(observer?: PartialObserver<T>): Subscription;
/** @deprecated Use an observer instead of a complete callback */
subscribe(next: null | undefined, error: null | undefined, complete: () => void): Subscription;
/** @deprecated Use an observer instead of an error callback */
subscribe(next: null | undefined, error: (error: any) => void, complete?: () => void): Subscription;
/** @deprecated Use an observer instead of a complete callback */
subscribe(next: (value: T) => void, error: null | undefined, complete: () => void): Subscription;
subscribe(next?: (value: T) => void, error?: (error: any) => void, complete?: () => void): Subscription;If I understand this correctly, in my case it should be using this signature :
subscribe(next?: (value: T) => void, error?: (error: any) => void, complete?: () => void): Subscription;Which is not deprecated
🙂 Expected behavior
There should be no deprecation warning