throw error inside rxjs Observable

Question

I'm trying to throw an error inside a rxjs Observable

 new Observable(subscriber => {
   Observable.throw("error1");
   return Observable.throw("error2");
 })
 .subscribe(
   () => {},
   err => console.error(err)
 );

error 1 is not caught.

error2 gives a compilation error:

Argument of type '(this: Observable<{}>, subscriber: Subscriber<{}>) => ErrorObservable<string>' is not assignable to parameter of type '(this: Observable<{}>, subscriber: Subscriber<{}>) => TeardownLogic'. Type 'ErrorObservable<string>' is not assignable to type 'TeardownLogic'

what is the proper way to throw an error inside an observable?

Answer 1

Use Subscriber.error:

new Rx.Observable(subscriber => {
  subscriber.error("error1");
  subscriber.error("error2"); // not called because a stream will be finalized after any error
})
.subscribe(
  () => {},
  err => console.error(err)
);

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