73 lines
2.6 KiB
TypeScript
73 lines
2.6 KiB
TypeScript
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import { Operator } from '../Operator';
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import { Subscriber } from '../Subscriber';
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import { ObservableInput, OperatorFunction } from '../types';
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import { SimpleOuterSubscriber } from '../innerSubscribe';
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/**
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* Applies an accumulator function over the source Observable where the
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* accumulator function itself returns an Observable, then each intermediate
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* Observable returned is merged into the output Observable.
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*
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* <span class="informal">It's like {@link scan}, but the Observables returned
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* by the accumulator are merged into the outer Observable.</span>
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*
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* ## Example
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* Count the number of click events
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* ```ts
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* import { fromEvent, of } from 'rxjs';
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* import { mapTo, mergeScan } from 'rxjs/operators';
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*
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* const click$ = fromEvent(document, 'click');
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* const one$ = click$.pipe(mapTo(1));
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* const seed = 0;
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* const count$ = one$.pipe(
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* mergeScan((acc, one) => of(acc + one), seed),
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* );
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* count$.subscribe(x => console.log(x));
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*
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* // Results:
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* // 1
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* // 2
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* // 3
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* // 4
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* // ...and so on for each click
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* ```
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*
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* @param {function(acc: R, value: T): Observable<R>} accumulator
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* The accumulator function called on each source value.
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* @param seed The initial accumulation value.
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* @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of
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* input Observables being subscribed to concurrently.
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* @return {Observable<R>} An observable of the accumulated values.
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* @method mergeScan
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* @owner Observable
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*/
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export declare function mergeScan<T, R>(accumulator: (acc: R, value: T, index: number) => ObservableInput<R>, seed: R, concurrent?: number): OperatorFunction<T, R>;
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export declare class MergeScanOperator<T, R> implements Operator<T, R> {
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private accumulator;
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private seed;
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private concurrent;
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constructor(accumulator: (acc: R, value: T, index: number) => ObservableInput<R>, seed: R, concurrent: number);
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call(subscriber: Subscriber<R>, source: any): any;
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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export declare class MergeScanSubscriber<T, R> extends SimpleOuterSubscriber<T, R> {
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private accumulator;
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private acc;
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private concurrent;
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private hasValue;
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private hasCompleted;
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private buffer;
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private active;
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protected index: number;
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constructor(destination: Subscriber<R>, accumulator: (acc: R, value: T, index: number) => ObservableInput<R>, acc: R, concurrent: number);
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protected _next(value: any): void;
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private _innerSub;
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protected _complete(): void;
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notifyNext(innerValue: R): void;
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notifyComplete(): void;
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}
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