import { Operator } from '../Operator';
import { Subscriber } from '../Subscriber';
import { Observable } from '../Observable';
import { OperatorFunction } from '../types';
import { SimpleOuterSubscriber, innerSubscribe, SimpleInnerSubscriber } from '../innerSubscribe';
/**
* Buffers the source Observable values until `closingNotifier` emits.
*
* Collects values from the past as an array, and emits
* that array only when another Observable emits.
*
* ![](buffer.png)
*
* 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
*
* On every click, emit array of most recent interval events
*
* ```ts
* import { fromEvent, interval } from 'rxjs';
* import { buffer } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const intervalEvents = interval(1000);
* const buffered = intervalEvents.pipe(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} closingNotifier An Observable that signals the
* buffer to be emitted on the output Observable.
* @return {Observable} An Observable of buffers, which are arrays of
* values.
* @method buffer
* @owner Observable
*/
export function buffer(closingNotifier: Observable): OperatorFunction {
return function bufferOperatorFunction(source: Observable) {
return source.lift(new BufferOperator(closingNotifier));
};
}
class BufferOperator implements Operator {
constructor(private closingNotifier: Observable) {
}
call(subscriber: Subscriber, source: any): any {
return source.subscribe(new BufferSubscriber(subscriber, this.closingNotifier));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
class BufferSubscriber extends SimpleOuterSubscriber {
private buffer: T[] = [];
constructor(destination: Subscriber, closingNotifier: Observable) {
super(destination);
this.add(innerSubscribe(closingNotifier, new SimpleInnerSubscriber(this)));
}
protected _next(value: T) {
this.buffer.push(value);
}
notifyNext(): void {
const buffer = this.buffer;
this.buffer = [];
this.destination.next!(buffer);
}
}