RxJs: How to return result in finalize

The finalize‘s callback is called during the teardown phase, e.g when the subscriptions are being unsubscribed. This may happen as a result of complete/error notifications. The callback’s return value won’t be taken into account.

What you can to instead is to use the endWith operator. So you could replace finalize like this:

/* ... */
endWith({type: ResponseType.writeComplete})
/* ... */

As we can see from its implementation

export function endWith<T>(...values: Array<T | SchedulerLike>): MonoTypeOperatorFunction<T> {
  return (source: Observable<T>) => concat(source, of(...values)) as Observable<T>;
}

endWith can take in multiple arguments,