| import { Operator } from '../Operator'; |
| import { Subscriber } from '../Subscriber'; |
| import { Observable } from '../Observable'; |
| import { Subscription } from '../Subscription'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| import { InnerSubscriber } from '../InnerSubscriber'; |
| import { OperatorFunction, SubscribableOrPromise } from '../types'; |
| |
| /** |
| * Buffers the source Observable values starting from an emission from |
| * `openings` and ending when the output of `closingSelector` emits. |
| * |
| * <span class="informal">Collects values from the past as an array. Starts |
| * collecting only when `opening` emits, and calls the `closingSelector` |
| * function to get an Observable that tells when to close the buffer.</span> |
| * |
| * ![](bufferToggle.png) |
| * |
| * Buffers values from the source by opening the buffer via signals from an |
| * Observable provided to `openings`, and closing and sending the buffers when |
| * a Subscribable or Promise returned by the `closingSelector` function emits. |
| * |
| * ## Example |
| * |
| * Every other second, emit the click events from the next 500ms |
| * |
| * ```ts |
| * import { fromEvent, interval, EMPTY } from 'rxjs'; |
| * import { bufferToggle } from 'rxjs/operators'; |
| * |
| * const clicks = fromEvent(document, 'click'); |
| * const openings = interval(1000); |
| * const buffered = clicks.pipe(bufferToggle(openings, i => |
| * i % 2 ? interval(500) : EMPTY |
| * )); |
| * buffered.subscribe(x => console.log(x)); |
| * ``` |
| * |
| * @see {@link buffer} |
| * @see {@link bufferCount} |
| * @see {@link bufferTime} |
| * @see {@link bufferWhen} |
| * @see {@link windowToggle} |
| * |
| * @param {SubscribableOrPromise<O>} openings A Subscribable or Promise of notifications to start new |
| * buffers. |
| * @param {function(value: O): SubscribableOrPromise} closingSelector A function that takes |
| * the value emitted by the `openings` observable and returns a Subscribable or Promise, |
| * which, when it emits, signals that the associated buffer should be emitted |
| * and cleared. |
| * @return {Observable<T[]>} An observable of arrays of buffered values. |
| * @method bufferToggle |
| * @owner Observable |
| */ |
| export function bufferToggle<T, O>( |
| openings: SubscribableOrPromise<O>, |
| closingSelector: (value: O) => SubscribableOrPromise<any> |
| ): OperatorFunction<T, T[]> { |
| return function bufferToggleOperatorFunction(source: Observable<T>) { |
| return source.lift(new BufferToggleOperator<T, O>(openings, closingSelector)); |
| }; |
| } |
| |
| class BufferToggleOperator<T, O> implements Operator<T, T[]> { |
| |
| constructor(private openings: SubscribableOrPromise<O>, |
| private closingSelector: (value: O) => SubscribableOrPromise<any>) { |
| } |
| |
| call(subscriber: Subscriber<T[]>, source: any): any { |
| return source.subscribe(new BufferToggleSubscriber(subscriber, this.openings, this.closingSelector)); |
| } |
| } |
| |
| interface BufferContext<T> { |
| buffer: T[]; |
| subscription: Subscription; |
| } |
| |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| class BufferToggleSubscriber<T, O> extends OuterSubscriber<T, O> { |
| private contexts: Array<BufferContext<T>> = []; |
| |
| constructor(destination: Subscriber<T[]>, |
| private openings: SubscribableOrPromise<O>, |
| private closingSelector: (value: O) => SubscribableOrPromise<any> | void) { |
| super(destination); |
| this.add(subscribeToResult(this, openings)); |
| } |
| |
| protected _next(value: T): void { |
| const contexts = this.contexts; |
| const len = contexts.length; |
| for (let i = 0; i < len; i++) { |
| contexts[i].buffer.push(value); |
| } |
| } |
| |
| protected _error(err: any): void { |
| const contexts = this.contexts; |
| while (contexts.length > 0) { |
| const context = contexts.shift(); |
| context.subscription.unsubscribe(); |
| context.buffer = null; |
| context.subscription = null; |
| } |
| this.contexts = null; |
| super._error(err); |
| } |
| |
| protected _complete(): void { |
| const contexts = this.contexts; |
| while (contexts.length > 0) { |
| const context = contexts.shift(); |
| this.destination.next(context.buffer); |
| context.subscription.unsubscribe(); |
| context.buffer = null; |
| context.subscription = null; |
| } |
| this.contexts = null; |
| super._complete(); |
| } |
| |
| notifyNext(outerValue: any, innerValue: O, |
| outerIndex: number, innerIndex: number, |
| innerSub: InnerSubscriber<T, O>): void { |
| outerValue ? this.closeBuffer(outerValue) : this.openBuffer(innerValue); |
| } |
| |
| notifyComplete(innerSub: InnerSubscriber<T, O>): void { |
| this.closeBuffer((<any> innerSub).context); |
| } |
| |
| private openBuffer(value: O): void { |
| try { |
| const closingSelector = this.closingSelector; |
| const closingNotifier = closingSelector.call(this, value); |
| if (closingNotifier) { |
| this.trySubscribe(closingNotifier); |
| } |
| } catch (err) { |
| this._error(err); |
| } |
| } |
| |
| private closeBuffer(context: BufferContext<T>): void { |
| const contexts = this.contexts; |
| |
| if (contexts && context) { |
| const { buffer, subscription } = context; |
| this.destination.next(buffer); |
| contexts.splice(contexts.indexOf(context), 1); |
| this.remove(subscription); |
| subscription.unsubscribe(); |
| } |
| } |
| |
| private trySubscribe(closingNotifier: any): void { |
| const contexts = this.contexts; |
| |
| const buffer: Array<T> = []; |
| const subscription = new Subscription(); |
| const context = { buffer, subscription }; |
| contexts.push(context); |
| |
| const innerSubscription = subscribeToResult(this, closingNotifier, <any>context); |
| |
| if (!innerSubscription || innerSubscription.closed) { |
| this.closeBuffer(context); |
| } else { |
| (<any> innerSubscription).context = context; |
| |
| this.add(innerSubscription); |
| subscription.add(innerSubscription); |
| } |
| } |
| } |