[6a3a178] | 1 | import { Operator } from '../Operator';
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| 2 | import { Subscriber } from '../Subscriber';
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| 3 | import { Observable } from '../Observable';
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| 4 | import { Subscription } from '../Subscription';
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| 5 | import { OperatorFunction } from '../types';
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| 6 | import { SimpleOuterSubscriber, innerSubscribe, SimpleInnerSubscriber } from '../innerSubscribe';
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| 7 |
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| 8 | /**
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| 9 | * Buffers the source Observable values, using a factory function of closing
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| 10 | * Observables to determine when to close, emit, and reset the buffer.
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| 11 | *
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| 12 | * <span class="informal">Collects values from the past as an array. When it
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| 13 | * starts collecting values, it calls a function that returns an Observable that
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| 14 | * tells when to close the buffer and restart collecting.</span>
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| 15 | *
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| 16 | * ![](bufferWhen.png)
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| 17 | *
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| 18 | * Opens a buffer immediately, then closes the buffer when the observable
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| 19 | * returned by calling `closingSelector` function emits a value. When it closes
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| 20 | * the buffer, it immediately opens a new buffer and repeats the process.
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| 21 | *
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| 22 | * ## Example
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| 23 | *
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| 24 | * Emit an array of the last clicks every [1-5] random seconds
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| 25 | *
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| 26 | * ```ts
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| 27 | * import { fromEvent, interval } from 'rxjs';
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| 28 | * import { bufferWhen } from 'rxjs/operators';
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| 29 | *
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| 30 | * const clicks = fromEvent(document, 'click');
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| 31 | * const buffered = clicks.pipe(bufferWhen(() =>
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| 32 | * interval(1000 + Math.random() * 4000)
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| 33 | * ));
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| 34 | * buffered.subscribe(x => console.log(x));
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| 35 | * ```
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| 36 | *
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| 37 | *
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| 38 | * @see {@link buffer}
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| 39 | * @see {@link bufferCount}
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| 40 | * @see {@link bufferTime}
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| 41 | * @see {@link bufferToggle}
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| 42 | * @see {@link windowWhen}
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| 43 | *
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| 44 | * @param {function(): Observable} closingSelector A function that takes no
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| 45 | * arguments and returns an Observable that signals buffer closure.
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| 46 | * @return {Observable<T[]>} An observable of arrays of buffered values.
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| 47 | * @method bufferWhen
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| 48 | * @owner Observable
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| 49 | */
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| 50 | export function bufferWhen<T>(closingSelector: () => Observable<any>): OperatorFunction<T, T[]> {
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| 51 | return function (source: Observable<T>) {
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| 52 | return source.lift(new BufferWhenOperator(closingSelector));
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| 53 | };
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| 54 | }
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| 55 |
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| 56 | class BufferWhenOperator<T> implements Operator<T, T[]> {
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| 57 |
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| 58 | constructor(private closingSelector: () => Observable<any>) {
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| 59 | }
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| 60 |
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| 61 | call(subscriber: Subscriber<T[]>, source: any): any {
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| 62 | return source.subscribe(new BufferWhenSubscriber(subscriber, this.closingSelector));
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| 63 | }
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| 64 | }
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| 65 |
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| 66 | /**
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| 67 | * We need this JSDoc comment for affecting ESDoc.
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| 68 | * @ignore
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| 69 | * @extends {Ignored}
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| 70 | */
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| 71 | class BufferWhenSubscriber<T> extends SimpleOuterSubscriber<T, any> {
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| 72 | private buffer?: T[];
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| 73 | private subscribing: boolean = false;
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| 74 | private closingSubscription?: Subscription;
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| 75 |
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| 76 | constructor(destination: Subscriber<T[]>, private closingSelector: () => Observable<any>) {
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| 77 | super(destination);
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| 78 | this.openBuffer();
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| 79 | }
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| 80 |
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| 81 | protected _next(value: T) {
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| 82 | this.buffer!.push(value);
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| 83 | }
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| 84 |
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| 85 | protected _complete() {
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| 86 | const buffer = this.buffer;
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| 87 | if (buffer) {
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| 88 | this.destination.next!(buffer);
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| 89 | }
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| 90 | super._complete();
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| 91 | }
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| 92 |
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| 93 | /** @deprecated This is an internal implementation detail, do not use. */
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| 94 | _unsubscribe() {
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| 95 | this.buffer = undefined;
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| 96 | this.subscribing = false;
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| 97 | }
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| 98 |
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| 99 | notifyNext(): void {
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| 100 | this.openBuffer();
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| 101 | }
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| 102 |
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| 103 | notifyComplete(): void {
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| 104 | if (this.subscribing) {
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| 105 | this.complete();
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| 106 | } else {
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| 107 | this.openBuffer();
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| 108 | }
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| 109 | }
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| 110 |
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| 111 | openBuffer() {
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| 112 | let { closingSubscription } = this;
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| 113 |
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| 114 | if (closingSubscription) {
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| 115 | this.remove(closingSubscription);
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| 116 | closingSubscription.unsubscribe();
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| 117 | }
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| 118 |
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| 119 | const buffer = this.buffer;
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| 120 | if (this.buffer) {
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| 121 | this.destination.next!(buffer);
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| 122 | }
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| 123 |
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| 124 | this.buffer = [];
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| 125 |
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| 126 | let closingNotifier;
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| 127 | try {
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| 128 | const { closingSelector } = this;
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| 129 | closingNotifier = closingSelector();
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| 130 | } catch (err) {
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| 131 | return this.error(err);
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| 132 | }
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| 133 | closingSubscription = new Subscription();
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| 134 | this.closingSubscription = closingSubscription;
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| 135 | this.add(closingSubscription);
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| 136 | this.subscribing = true;
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| 137 | closingSubscription.add(innerSubscribe(closingNotifier, new SimpleInnerSubscriber(this)));
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| 138 | this.subscribing = false;
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| 139 | }
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| 140 | }
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