RxJS Observable: repeat using count and then using notifier - rxjs

Question

I have an Observable that emits Either = Success | Failure:
import { Observable } from 'rxjs';
type Success = { type: 'success' };
type Failure = { type: 'failure' };
type Either = Success | Failure;
const either$ = new Observable<Either>(observer => {
console.log('subscribe');
observer.next({ type: 'failure' });
observer.complete();
return () => {
console.log('unsubscribe');
};
});
I want to allow the user to "retry" the observable when the Observable completes and the last value was Failure.
(The retry{,When} operators do not help here because they work with errors on the error channel. For this reason, I believe we should think in terms of repeat instead.)
I want to:
Repeat the Observable n times until the last value is not Failure.
Then, allow the user to repeat manually. When a repeat notifier observable (repeat$) emits, repeat the observable again.
For example:
// subscribe
// next { type: 'failure' }
// unsubscribe
// retry 2 times:
// subscribe
// next { type: 'failure' }
// unsubscribe
// subscribe
// next { type: 'failure' }
// unsubscribe
// now, wait for repeat notifications…
// on retry notification:
// subscribe
// next { type: 'failure' }
// unsubscribe

Answer 1

I couldn't come up with something simpler, but the code does what you want.
See https://stackblitz.com/edit/typescript-yqcejk
defer(() => {
let retries = 0;
const source = new BehaviorSubject(null);
return merge(source, repeat$.pipe(filter(() => retries <= MAX_RETRIES)))
.pipe(
concatMapTo(either$),
tap(value => {
const action = value as Either;
if (action.type === 'failure') {
if (retries < MAX_RETRIES) {
retries += 1;
source.next(null);
}
} else {
retries = 0;
}
})
)
}).subscribe(console.log);
I had to manually count retries.
The code has two sources of events source for automatic retries and repeat$ for user retries. All events are mapped to either$ using concatMapTo. As a side-effect we either next() to retry or do nothing waiting for user to retry.
User retries are suppressed using filter(() => retries >= MAX_RETRIES) until MAX_RETRIES count is reached.