import { Observable } from '../Observable';
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import { innerFrom } from '../observable/innerFrom';
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import { Subject } from '../Subject';
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import { Subscription } from '../Subscription';
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import { MonoTypeOperatorFunction, ObservableInput } from '../types';
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import { operate } from '../util/lift';
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import { createOperatorSubscriber } from './OperatorSubscriber';
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/**
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* Returns an Observable that mirrors the source Observable with the exception of an `error`. If the source Observable
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* calls `error`, this method will emit the Throwable that caused the error to the `ObservableInput` returned from `notifier`.
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* If that Observable calls `complete` or `error` then this method will call `complete` or `error` on the child
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* subscription. Otherwise this method will resubscribe to the source Observable.
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*
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* 
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*
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* Retry an observable sequence on error based on custom criteria.
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*
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* ## Example
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*
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* ```ts
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* import { interval, map, retryWhen, tap, delayWhen, timer } from 'rxjs';
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*
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* const source = interval(1000);
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* const result = source.pipe(
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* map(value => {
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* if (value > 5) {
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* // error will be picked up by retryWhen
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* throw value;
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* }
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* return value;
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* }),
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* retryWhen(errors =>
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* errors.pipe(
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* // log error message
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* tap(value => console.log(`Value ${ value } was too high!`)),
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* // restart in 5 seconds
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* delayWhen(value => timer(value * 1000))
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* )
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* )
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* );
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*
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* result.subscribe(value => console.log(value));
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*
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* // results:
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* // 0
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* // 1
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* // 2
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* // 3
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* // 4
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* // 5
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* // 'Value 6 was too high!'
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* // - Wait 5 seconds then repeat
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* ```
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*
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* @see {@link retry}
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*
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* @param notifier Function that receives an Observable of notifications with which a
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* user can `complete` or `error`, aborting the retry.
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* @return A function that returns an `ObservableInput` that mirrors the source
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* Observable with the exception of an `error`.
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* @deprecated Will be removed in v9 or v10, use {@link retry}'s `delay` option instead.
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* Will be removed in v9 or v10. Use {@link retry}'s {@link RetryConfig#delay delay} option instead.
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* Instead of `retryWhen(() => notify$)`, use: `retry({ delay: () => notify$ })`.
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*/
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export function retryWhen<T>(notifier: (errors: Observable<any>) => ObservableInput<any>): MonoTypeOperatorFunction<T> {
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return operate((source, subscriber) => {
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let innerSub: Subscription | null;
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let syncResub = false;
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let errors$: Subject<any>;
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const subscribeForRetryWhen = () => {
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innerSub = source.subscribe(
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createOperatorSubscriber(subscriber, undefined, undefined, (err) => {
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if (!errors$) {
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errors$ = new Subject();
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innerFrom(notifier(errors$)).subscribe(
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createOperatorSubscriber(subscriber, () =>
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// If we have an innerSub, this was an asynchronous call, kick off the retry.
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// Otherwise, if we don't have an innerSub yet, that's because the inner subscription
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// call hasn't even returned yet. We've arrived here synchronously.
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// So we flag that we want to resub, such that we can ensure finalization
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// happens before we resubscribe.
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innerSub ? subscribeForRetryWhen() : (syncResub = true)
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)
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);
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}
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if (errors$) {
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// We have set up the notifier without error.
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errors$.next(err);
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}
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})
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);
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if (syncResub) {
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// Ensure that the inner subscription is torn down before
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// moving on to the next subscription in the synchronous case.
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// If we don't do this here, all inner subscriptions will not be
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// torn down until the entire observable is done.
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innerSub.unsubscribe();
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innerSub = null;
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// We may need to do this multiple times, so reset the flag.
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syncResub = false;
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// Resubscribe
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subscribeForRetryWhen();
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}
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};
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// Start the subscription
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subscribeForRetryWhen();
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});
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}
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