mergeMapTo.ts
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import { Observable } from '../Observable';
import { OperatorFunction, ObservedValueOf } from '../../internal/types';
import { mergeMap } from './mergeMap';
import { ObservableInput } from '../types';
/* tslint:disable:max-line-length */
export function mergeMapTo<T, O extends ObservableInput<any>>(innerObservable: O, concurrent?: number): OperatorFunction<any, ObservedValueOf<O>>;
/** @deprecated */
export function mergeMapTo<T, R, O extends ObservableInput<any>>(innerObservable: O, resultSelector: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R, concurrent?: number): OperatorFunction<T, R>;
/* tslint:enable:max-line-length */
/**
* Projects each source value to the same Observable which is merged multiple
* times in the output Observable.
*
* <span class="informal">It's like {@link mergeMap}, but maps each value always
* to the same inner Observable.</span>
*
* 
*
* Maps each source value to the given Observable `innerObservable` regardless
* of the source value, and then merges those resulting Observables into one
* single Observable, which is the output Observable.
*
* ## Example
* For each click event, start an interval Observable ticking every 1 second
* ```ts
* import { fromEvent, interval } from 'rxjs';
* import { mergeMapTo } from 'rxjs/operators';
*
* const clicks = fromEvent(document, 'click');
* const result = clicks.pipe(mergeMapTo(interval(1000)));
* result.subscribe(x => console.log(x));
* ```
*
* @see {@link concatMapTo}
* @see {@link merge}
* @see {@link mergeAll}
* @see {@link mergeMap}
* @see {@link mergeScan}
* @see {@link switchMapTo}
*
* @param {ObservableInput} innerObservable An Observable to replace each value from
* the source Observable.
* @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of input
* Observables being subscribed to concurrently.
* @return {Observable} An Observable that emits items from the given
* `innerObservable`
* @method mergeMapTo
* @owner Observable
*/
export function mergeMapTo<T, R, O extends ObservableInput<any>>(
innerObservable: O,
resultSelector?: ((outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R) | number,
concurrent: number = Number.POSITIVE_INFINITY
): OperatorFunction<T, ObservedValueOf<O>|R> {
if (typeof resultSelector === 'function') {
return mergeMap(() => innerObservable, resultSelector, concurrent);
}
if (typeof resultSelector === 'number') {
concurrent = resultSelector;
}
return mergeMap(() => innerObservable, concurrent);
}