import {Operator} from '../Operator';
import {Subscriber} from '../Subscriber';
import {Observable} from '../Observable';
/**
* Returns an Observable that mirrors the source Observable, resubscribing to it if it calls `error` and the
* predicate returns true for that specific exception and retry count.
* If the source Observable calls `error`, this method will resubscribe to the source Observable for a maximum of
* count resubscriptions (given as a number parameter) rather than propagating the `error` call.
*
* <img src="./img/retry.png" width="100%">
*
* Any and all items emitted by the source Observable will be emitted by the resulting Observable, even those emitted
* during failed subscriptions. For example, if an Observable fails at first but emits [1, 2] then succeeds the second
* time and emits: [1, 2, 3, 4, 5] then the complete stream of emissions and notifications
* would be: [1, 2, 1, 2, 3, 4, 5, `complete`].
* @param {number} number of retry attempts before failing.
* @returns {Observable} the source Observable modified with the retry logic.
*/
export function retry<T>(count: number = -1): Observable<T> {
return this.lift(new RetryOperator(count, this));
}
class RetryOperator<T> implements Operator<T, T> {
constructor(private count: number,
private source: Observable<T>) {
}
call(subscriber: Subscriber<T>): Subscriber<T> {
return new RetrySubscriber(subscriber, this.count, this.source);
}
}
class RetrySubscriber<T> extends Subscriber<T> {
constructor(destination: Subscriber<any>,
private count: number,
private source: Observable<T>) {
super(destination);
}
error(err: any) {
Eif (!this.isStopped) {
const { source, count } = this;
if (count === 0) {
return super.error(err);
} else if (count > -1) {
this.count = count - 1;
}
this.unsubscribe();
this.isStopped = false;
this.isUnsubscribed = false;
source.subscribe(this);
}
}
}
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