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feat(buffer): add higher-order lettable version of buffer
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benlesh committed Jul 13, 2017
1 parent ce42477 commit d8ca9de
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Showing 3 changed files with 85 additions and 43 deletions.
46 changes: 3 additions & 43 deletions src/operator/buffer.ts
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@@ -1,10 +1,6 @@
import { Operator } from '../Operator';
import { Subscriber } from '../Subscriber';
import { Observable } from '../Observable';

import { OuterSubscriber } from '../OuterSubscriber';
import { InnerSubscriber } from '../InnerSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
import { Observable } from '../Observable';
import { buffer as higherOrder } from '../operators';

/**
* Buffers the source Observable values until `closingNotifier` emits.
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* @owner Observable
*/
export function buffer<T>(this: Observable<T>, closingNotifier: Observable<any>): Observable<T[]> {
return this.lift(new BufferOperator<T>(closingNotifier));
}

class BufferOperator<T> implements Operator<T, T[]> {

constructor(private closingNotifier: Observable<any>) {
}

call(subscriber: Subscriber<T[]>, source: any): any {
return source.subscribe(new BufferSubscriber(subscriber, this.closingNotifier));
}
}

/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class BufferSubscriber<T> extends OuterSubscriber<T, any> {
private buffer: T[] = [];

constructor(destination: Subscriber<T[]>, closingNotifier: Observable<any>) {
super(destination);
this.add(subscribeToResult(this, closingNotifier));
}

protected _next(value: T) {
this.buffer.push(value);
}

notifyNext(outerValue: T, innerValue: any,
outerIndex: number, innerIndex: number,
innerSub: InnerSubscriber<T, any>): void {
const buffer = this.buffer;
this.buffer = [];
this.destination.next(buffer);
}
return higherOrder(closingNotifier)(this);
}
81 changes: 81 additions & 0 deletions src/operators/buffer.ts
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import { Operator } from '../Operator';
import { Subscriber } from '../Subscriber';
import { Observable } from '../Observable';
import { OuterSubscriber } from '../OuterSubscriber';
import { InnerSubscriber } from '../InnerSubscriber';
import { subscribeToResult } from '../util/subscribeToResult';
import { OperatorFunction } from '../interfaces';

/**
* Buffers the source Observable values until `closingNotifier` emits.
*
* <span class="informal">Collects values from the past as an array, and emits
* that array only when another Observable emits.</span>
*
* <img src="./img/buffer.png" width="100%">
*
* Buffers the incoming Observable values until the given `closingNotifier`
* Observable emits a value, at which point it emits the buffer on the output
* Observable and starts a new buffer internally, awaiting the next time
* `closingNotifier` emits.
*
* @example <caption>On every click, emit array of most recent interval events</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var interval = Rx.Observable.interval(1000);
* var buffered = interval.buffer(clicks);
* buffered.subscribe(x => console.log(x));
*
* @see {@link bufferCount}
* @see {@link bufferTime}
* @see {@link bufferToggle}
* @see {@link bufferWhen}
* @see {@link window}
*
* @param {Observable<any>} closingNotifier An Observable that signals the
* buffer to be emitted on the output Observable.
* @return {Observable<T[]>} An Observable of buffers, which are arrays of
* values.
* @method buffer
* @owner Observable
*/
export function buffer<T>(closingNotifier: Observable<any>): OperatorFunction<T, T[]> {
return function bufferOperatorFunction(source: Observable<T>) {
return source.lift(new BufferOperator<T>(closingNotifier));
};
}

class BufferOperator<T> implements Operator<T, T[]> {

constructor(private closingNotifier: Observable<any>) {
}

call(subscriber: Subscriber<T[]>, source: any): any {
return source.subscribe(new BufferSubscriber(subscriber, this.closingNotifier));
}
}

/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class BufferSubscriber<T> extends OuterSubscriber<T, any> {
private buffer: T[] = [];

constructor(destination: Subscriber<T[]>, closingNotifier: Observable<any>) {
super(destination);
this.add(subscribeToResult(this, closingNotifier));
}

protected _next(value: T) {
this.buffer.push(value);
}

notifyNext(outerValue: T, innerValue: any,
outerIndex: number, innerIndex: number,
innerSub: InnerSubscriber<T, any>): void {
const buffer = this.buffer;
this.buffer = [];
this.destination.next(buffer);
}
}
1 change: 1 addition & 0 deletions src/operators/index.ts
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@@ -1,5 +1,6 @@
export { audit } from './audit';
export { auditTime } from './auditTime';
export { buffer } from './buffer';
export { catchError } from './catchError';
export { concat } from './concat';
export { concatAll } from './concatAll';
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