| import { Subscriber } from '../Subscriber'; |
| import { Observable } from '../Observable'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| /** |
| * Delays the emission of items from the source Observable by a given time span |
| * determined by the emissions of another Observable. |
| * |
| * <span class="informal">It's like {@link delay}, but the time span of the |
| * delay duration is determined by a second Observable.</span> |
| * |
| * <img src="./img/delayWhen.png" width="100%"> |
| * |
| * `delayWhen` time shifts each emitted value from the source Observable by a |
| * time span determined by another Observable. When the source emits a value, |
| * the `delayDurationSelector` function is called with the source value as |
| * argument, and should return an Observable, called the "duration" Observable. |
| * The source value is emitted on the output Observable only when the duration |
| * Observable emits a value or completes. |
| * |
| * Optionally, `delayWhen` takes a second argument, `subscriptionDelay`, which |
| * is an Observable. When `subscriptionDelay` emits its first value or |
| * completes, the source Observable is subscribed to and starts behaving like |
| * described in the previous paragraph. If `subscriptionDelay` is not provided, |
| * `delayWhen` will subscribe to the source Observable as soon as the output |
| * Observable is subscribed. |
| * |
| * @example <caption>Delay each click by a random amount of time, between 0 and 5 seconds</caption> |
| * var clicks = Rx.Observable.fromEvent(document, 'click'); |
| * var delayedClicks = clicks.delayWhen(event => |
| * Rx.Observable.interval(Math.random() * 5000) |
| * ); |
| * delayedClicks.subscribe(x => console.log(x)); |
| * |
| * @see {@link debounce} |
| * @see {@link delay} |
| * |
| * @param {function(value: T): Observable} delayDurationSelector A function that |
| * returns an Observable for each value emitted by the source Observable, which |
| * is then used to delay the emission of that item on the output Observable |
| * until the Observable returned from this function emits a value. |
| * @param {Observable} subscriptionDelay An Observable that triggers the |
| * subscription to the source Observable once it emits any value. |
| * @return {Observable} An Observable that delays the emissions of the source |
| * Observable by an amount of time specified by the Observable returned by |
| * `delayDurationSelector`. |
| * @method delayWhen |
| * @owner Observable |
| */ |
| export function delayWhen(delayDurationSelector, subscriptionDelay) { |
| if (subscriptionDelay) { |
| return (source) => new SubscriptionDelayObservable(source, subscriptionDelay) |
| .lift(new DelayWhenOperator(delayDurationSelector)); |
| } |
| return (source) => source.lift(new DelayWhenOperator(delayDurationSelector)); |
| } |
| class DelayWhenOperator { |
| constructor(delayDurationSelector) { |
| this.delayDurationSelector = delayDurationSelector; |
| } |
| call(subscriber, source) { |
| return source.subscribe(new DelayWhenSubscriber(subscriber, this.delayDurationSelector)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class DelayWhenSubscriber extends OuterSubscriber { |
| constructor(destination, delayDurationSelector) { |
| super(destination); |
| this.delayDurationSelector = delayDurationSelector; |
| this.completed = false; |
| this.delayNotifierSubscriptions = []; |
| this.values = []; |
| } |
| notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
| this.destination.next(outerValue); |
| this.removeSubscription(innerSub); |
| this.tryComplete(); |
| } |
| notifyError(error, innerSub) { |
| this._error(error); |
| } |
| notifyComplete(innerSub) { |
| const value = this.removeSubscription(innerSub); |
| if (value) { |
| this.destination.next(value); |
| } |
| this.tryComplete(); |
| } |
| _next(value) { |
| try { |
| const delayNotifier = this.delayDurationSelector(value); |
| if (delayNotifier) { |
| this.tryDelay(delayNotifier, value); |
| } |
| } |
| catch (err) { |
| this.destination.error(err); |
| } |
| } |
| _complete() { |
| this.completed = true; |
| this.tryComplete(); |
| } |
| removeSubscription(subscription) { |
| subscription.unsubscribe(); |
| const subscriptionIdx = this.delayNotifierSubscriptions.indexOf(subscription); |
| let value = null; |
| if (subscriptionIdx !== -1) { |
| value = this.values[subscriptionIdx]; |
| this.delayNotifierSubscriptions.splice(subscriptionIdx, 1); |
| this.values.splice(subscriptionIdx, 1); |
| } |
| return value; |
| } |
| tryDelay(delayNotifier, value) { |
| const notifierSubscription = subscribeToResult(this, delayNotifier, value); |
| if (notifierSubscription && !notifierSubscription.closed) { |
| this.add(notifierSubscription); |
| this.delayNotifierSubscriptions.push(notifierSubscription); |
| } |
| this.values.push(value); |
| } |
| tryComplete() { |
| if (this.completed && this.delayNotifierSubscriptions.length === 0) { |
| this.destination.complete(); |
| } |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class SubscriptionDelayObservable extends Observable { |
| constructor(source, subscriptionDelay) { |
| super(); |
| this.source = source; |
| this.subscriptionDelay = subscriptionDelay; |
| } |
| _subscribe(subscriber) { |
| this.subscriptionDelay.subscribe(new SubscriptionDelaySubscriber(subscriber, this.source)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class SubscriptionDelaySubscriber extends Subscriber { |
| constructor(parent, source) { |
| super(); |
| this.parent = parent; |
| this.source = source; |
| this.sourceSubscribed = false; |
| } |
| _next(unused) { |
| this.subscribeToSource(); |
| } |
| _error(err) { |
| this.unsubscribe(); |
| this.parent.error(err); |
| } |
| _complete() { |
| this.subscribeToSource(); |
| } |
| subscribeToSource() { |
| if (!this.sourceSubscribed) { |
| this.sourceSubscribed = true; |
| this.unsubscribe(); |
| this.source.subscribe(this.parent); |
| } |
| } |
| } |
| //# sourceMappingURL=delayWhen.js.map |