import { Operator } from '../Operator';
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import { Subscriber } from '../Subscriber';
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import { Observable } from '../Observable';
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import { Subscription } from '../Subscription';
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import { OuterSubscriber } from '../OuterSubscriber';
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import { InnerSubscriber } from '../InnerSubscriber';
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import { subscribeToResult } from '../util/subscribeToResult';
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import { MonoTypeOperatorFunction, TeardownLogic } from '../types';
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/* tslint:disable:max-line-length */
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/** @deprecated In future versions, empty notifiers will no longer re-emit the source value on the output observable. */
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export function delayWhen<T>(delayDurationSelector: (value: T, index: number) => Observable<never>, subscriptionDelay?: Observable<any>): MonoTypeOperatorFunction<T>;
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export function delayWhen<T>(delayDurationSelector: (value: T, index: number) => Observable<any>, subscriptionDelay?: Observable<any>): MonoTypeOperatorFunction<T>;
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/* tslint:disable:max-line-length */
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/**
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* Delays the emission of items from the source Observable by a given time span
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* determined by the emissions of another Observable.
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*
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* <span class="informal">It's like {@link delay}, but the time span of the
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* delay duration is determined by a second Observable.</span>
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*
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* 
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*
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* `delayWhen` time shifts each emitted value from the source Observable by a
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* time span determined by another Observable. When the source emits a value,
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* the `delayDurationSelector` function is called with the source value as
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* argument, and should return an Observable, called the "duration" Observable.
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* The source value is emitted on the output Observable only when the duration
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* Observable emits a value or completes.
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* The completion of the notifier triggering the emission of the source value
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* is deprecated behavior and will be removed in future versions.
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*
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* Optionally, `delayWhen` takes a second argument, `subscriptionDelay`, which
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* is an Observable. When `subscriptionDelay` emits its first value or
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* completes, the source Observable is subscribed to and starts behaving like
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* described in the previous paragraph. If `subscriptionDelay` is not provided,
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* `delayWhen` will subscribe to the source Observable as soon as the output
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* Observable is subscribed.
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*
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* ## Example
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* Delay each click by a random amount of time, between 0 and 5 seconds
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* ```ts
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* import { fromEvent, interval } from 'rxjs';
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* import { delayWhen } from 'rxjs/operators';
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*
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* const clicks = fromEvent(document, 'click');
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* const delayedClicks = clicks.pipe(
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* delayWhen(event => interval(Math.random() * 5000)),
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* );
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* delayedClicks.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link debounce}
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* @see {@link delay}
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*
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* @param {function(value: T, index: number): Observable} delayDurationSelector A function that
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* returns an Observable for each value emitted by the source Observable, which
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* is then used to delay the emission of that item on the output Observable
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* until the Observable returned from this function emits a value.
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* @param {Observable} subscriptionDelay An Observable that triggers the
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* subscription to the source Observable once it emits any value.
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* @return {Observable} An Observable that delays the emissions of the source
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* Observable by an amount of time specified by the Observable returned by
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* `delayDurationSelector`.
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* @method delayWhen
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* @owner Observable
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*/
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export function delayWhen<T>(delayDurationSelector: (value: T, index: number) => Observable<any>,
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subscriptionDelay?: Observable<any>): MonoTypeOperatorFunction<T> {
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if (subscriptionDelay) {
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return (source: Observable<T>) =>
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new SubscriptionDelayObservable(source, subscriptionDelay)
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.lift(new DelayWhenOperator(delayDurationSelector));
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}
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return (source: Observable<T>) => source.lift(new DelayWhenOperator(delayDurationSelector));
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}
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class DelayWhenOperator<T> implements Operator<T, T> {
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constructor(private delayDurationSelector: (value: T, index: number) => Observable<any>) {
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}
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call(subscriber: Subscriber<T>, source: any): TeardownLogic {
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return source.subscribe(new DelayWhenSubscriber(subscriber, this.delayDurationSelector));
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class DelayWhenSubscriber<T, R> extends OuterSubscriber<T, R> {
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private completed: boolean = false;
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private delayNotifierSubscriptions: Array<Subscription> = [];
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private index: number = 0;
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constructor(destination: Subscriber<T>,
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private delayDurationSelector: (value: T, index: number) => Observable<any>) {
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super(destination);
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}
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notifyNext(outerValue: T, innerValue: any,
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outerIndex: number, innerIndex: number,
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innerSub: InnerSubscriber<T, R>): void {
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this.destination.next(outerValue);
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this.removeSubscription(innerSub);
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this.tryComplete();
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}
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notifyError(error: any, innerSub: InnerSubscriber<T, R>): void {
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this._error(error);
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}
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notifyComplete(innerSub: InnerSubscriber<T, R>): void {
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const value = this.removeSubscription(innerSub);
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if (value) {
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this.destination.next(value);
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}
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this.tryComplete();
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}
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protected _next(value: T): void {
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const index = this.index++;
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try {
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const delayNotifier = this.delayDurationSelector(value, index);
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if (delayNotifier) {
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this.tryDelay(delayNotifier, value);
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}
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} catch (err) {
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this.destination.error(err);
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}
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}
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protected _complete(): void {
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this.completed = true;
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this.tryComplete();
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this.unsubscribe();
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}
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private removeSubscription(subscription: InnerSubscriber<T, R>): T {
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subscription.unsubscribe();
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const subscriptionIdx = this.delayNotifierSubscriptions.indexOf(subscription);
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if (subscriptionIdx !== -1) {
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this.delayNotifierSubscriptions.splice(subscriptionIdx, 1);
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}
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return subscription.outerValue;
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}
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private tryDelay(delayNotifier: Observable<any>, value: T): void {
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const notifierSubscription = subscribeToResult(this, delayNotifier, value);
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if (notifierSubscription && !notifierSubscription.closed) {
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const destination = this.destination as Subscription;
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destination.add(notifierSubscription);
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this.delayNotifierSubscriptions.push(notifierSubscription);
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}
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}
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private tryComplete(): void {
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if (this.completed && this.delayNotifierSubscriptions.length === 0) {
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this.destination.complete();
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}
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class SubscriptionDelayObservable<T> extends Observable<T> {
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constructor(public source: Observable<T>, private subscriptionDelay: Observable<any>) {
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super();
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}
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/** @deprecated This is an internal implementation detail, do not use. */
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_subscribe(subscriber: Subscriber<T>) {
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this.subscriptionDelay.subscribe(new SubscriptionDelaySubscriber(subscriber, this.source));
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class SubscriptionDelaySubscriber<T> extends Subscriber<T> {
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private sourceSubscribed: boolean = false;
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constructor(private parent: Subscriber<T>, private source: Observable<T>) {
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super();
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}
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protected _next(unused: any) {
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this.subscribeToSource();
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}
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protected _error(err: any) {
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this.unsubscribe();
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this.parent.error(err);
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}
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protected _complete() {
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this.unsubscribe();
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this.subscribeToSource();
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}
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private subscribeToSource(): void {
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if (!this.sourceSubscribed) {
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this.sourceSubscribed = true;
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this.unsubscribe();
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this.source.subscribe(this.parent);
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}
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}
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}
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