work.suroh.tk/node_modules/rxjs/_esm2015/operators/delayWhen.js

178 lines
6.3 KiB
JavaScript
Raw Normal View History

2019-12-02 12:22:45 +00:00
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(/** @deprecated internal use only */ source, subscriptionDelay) {
super();
this.source = source;
this.subscriptionDelay = subscriptionDelay;
}
/** @deprecated internal use only */ _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