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Diffstat (limited to 'node_modules/rxjs/src/internal/operators/bufferToggle.ts')
| -rw-r--r-- | node_modules/rxjs/src/internal/operators/bufferToggle.ts | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/node_modules/rxjs/src/internal/operators/bufferToggle.ts b/node_modules/rxjs/src/internal/operators/bufferToggle.ts new file mode 100644 index 0000000..fabefbc --- /dev/null +++ b/node_modules/rxjs/src/internal/operators/bufferToggle.ts @@ -0,0 +1,102 @@ +import { Subscription } from '../Subscription'; +import { OperatorFunction, ObservableInput } from '../types'; +import { operate } from '../util/lift'; +import { innerFrom } from '../observable/innerFrom'; +import { createOperatorSubscriber } from './OperatorSubscriber'; +import { noop } from '../util/noop'; +import { arrRemove } from '../util/arrRemove'; + +/** + * 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> + * + *  + * + * 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, bufferToggle, EMPTY } from 'rxjs'; + * + * 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 openings A Subscribable or Promise of notifications to start new + * buffers. + * @param 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 A function that returns an Observable of arrays of buffered values. + */ +export function bufferToggle<T, O>( + openings: ObservableInput<O>, + closingSelector: (value: O) => ObservableInput<any> +): OperatorFunction<T, T[]> { + return operate((source, subscriber) => { + const buffers: T[][] = []; + + // Subscribe to the openings notifier first + innerFrom(openings).subscribe( + createOperatorSubscriber( + subscriber, + (openValue) => { + const buffer: T[] = []; + buffers.push(buffer); + // We use this composite subscription, so that + // when the closing notifier emits, we can tear it down. + const closingSubscription = new Subscription(); + + const emitBuffer = () => { + arrRemove(buffers, buffer); + subscriber.next(buffer); + closingSubscription.unsubscribe(); + }; + + // The line below will add the subscription to the parent subscriber *and* the closing subscription. + closingSubscription.add(innerFrom(closingSelector(openValue)).subscribe(createOperatorSubscriber(subscriber, emitBuffer, noop))); + }, + noop + ) + ); + + source.subscribe( + createOperatorSubscriber( + subscriber, + (value) => { + // Value from our source. Add it to all pending buffers. + for (const buffer of buffers) { + buffer.push(value); + } + }, + () => { + // Source complete. Emit all pending buffers. + while (buffers.length > 0) { + subscriber.next(buffers.shift()!); + } + subscriber.complete(); + } + ) + ); + }); +} |
