| import { tryCatch } from '../util/tryCatch'; |
| import { errorObject } from '../util/errorObject'; |
| import { subscribeToResult } from '../util/subscribeToResult'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| /** |
| * Applies an accumulator function over the source Observable where the |
| * accumulator function itself returns an Observable, then each intermediate |
| * Observable returned is merged into the output Observable. |
| * |
| * <span class="informal">It's like {@link scan}, but the Observables returned |
| * by the accumulator are merged into the outer Observable.</span> |
| * |
| * @example <caption>Count the number of click events</caption> |
| * const click$ = Rx.Observable.fromEvent(document, 'click'); |
| * const one$ = click$.mapTo(1); |
| * const seed = 0; |
| * const count$ = one$.mergeScan((acc, one) => Rx.Observable.of(acc + one), seed); |
| * count$.subscribe(x => console.log(x)); |
| * |
| * // Results: |
| * 1 |
| * 2 |
| * 3 |
| * 4 |
| * // ...and so on for each click |
| * |
| * @param {function(acc: R, value: T): Observable<R>} accumulator |
| * The accumulator function called on each source value. |
| * @param seed The initial accumulation value. |
| * @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of |
| * input Observables being subscribed to concurrently. |
| * @return {Observable<R>} An observable of the accumulated values. |
| * @method mergeScan |
| * @owner Observable |
| */ |
| export function mergeScan(accumulator, seed, concurrent = Number.POSITIVE_INFINITY) { |
| return (source) => source.lift(new MergeScanOperator(accumulator, seed, concurrent)); |
| } |
| export class MergeScanOperator { |
| constructor(accumulator, seed, concurrent) { |
| this.accumulator = accumulator; |
| this.seed = seed; |
| this.concurrent = concurrent; |
| } |
| call(subscriber, source) { |
| return source.subscribe(new MergeScanSubscriber(subscriber, this.accumulator, this.seed, this.concurrent)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| export class MergeScanSubscriber extends OuterSubscriber { |
| constructor(destination, accumulator, acc, concurrent) { |
| super(destination); |
| this.accumulator = accumulator; |
| this.acc = acc; |
| this.concurrent = concurrent; |
| this.hasValue = false; |
| this.hasCompleted = false; |
| this.buffer = []; |
| this.active = 0; |
| this.index = 0; |
| } |
| _next(value) { |
| if (this.active < this.concurrent) { |
| const index = this.index++; |
| const ish = tryCatch(this.accumulator)(this.acc, value); |
| const destination = this.destination; |
| if (ish === errorObject) { |
| destination.error(errorObject.e); |
| } |
| else { |
| this.active++; |
| this._innerSub(ish, value, index); |
| } |
| } |
| else { |
| this.buffer.push(value); |
| } |
| } |
| _innerSub(ish, value, index) { |
| this.add(subscribeToResult(this, ish, value, index)); |
| } |
| _complete() { |
| this.hasCompleted = true; |
| if (this.active === 0 && this.buffer.length === 0) { |
| if (this.hasValue === false) { |
| this.destination.next(this.acc); |
| } |
| this.destination.complete(); |
| } |
| } |
| notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
| const { destination } = this; |
| this.acc = innerValue; |
| this.hasValue = true; |
| destination.next(innerValue); |
| } |
| notifyComplete(innerSub) { |
| const buffer = this.buffer; |
| this.remove(innerSub); |
| this.active--; |
| if (buffer.length > 0) { |
| this._next(buffer.shift()); |
| } |
| else if (this.active === 0 && this.hasCompleted) { |
| if (this.hasValue === false) { |
| this.destination.next(this.acc); |
| } |
| this.destination.complete(); |
| } |
| } |
| } |
| //# sourceMappingURL=mergeScan.js.map |