????
Your IP : 3.12.148.147
import { mergeMap } from './mergeMap';
import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
import { isFunction } from '../util/isFunction';
/* tslint:disable:max-line-length */
export function concatMap<T, O extends ObservableInput<any>>(
project: (value: T, index: number) => O
): OperatorFunction<T, ObservedValueOf<O>>;
/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
export function concatMap<T, O extends ObservableInput<any>>(
project: (value: T, index: number) => O,
resultSelector: undefined
): OperatorFunction<T, ObservedValueOf<O>>;
/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
export function concatMap<T, R, O extends ObservableInput<any>>(
project: (value: T, index: number) => O,
resultSelector: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
): OperatorFunction<T, R>;
/* tslint:enable:max-line-length */
/**
* Projects each source value to an Observable which is merged in the output
* Observable, in a serialized fashion waiting for each one to complete before
* merging the next.
*
* <span class="informal">Maps each value to an Observable, then flattens all of
* these inner Observables using {@link concatAll}.</span>
*
* 
*
* Returns an Observable that emits items based on applying a function that you
* supply to each item emitted by the source Observable, where that function
* returns an (so-called "inner") Observable. Each new inner Observable is
* concatenated with the previous inner Observable.
*
* __Warning:__ if source values arrive endlessly and faster than their
* corresponding inner Observables can complete, it will result in memory issues
* as inner Observables amass in an unbounded buffer waiting for their turn to
* be subscribed to.
*
* Note: `concatMap` is equivalent to `mergeMap` with concurrency parameter set
* to `1`.
*
* ## Example
*
* For each click event, tick every second from 0 to 3, with no concurrency
*
* ```ts
* import { fromEvent, concatMap, interval, take } from 'rxjs';
*
* const clicks = fromEvent(document, 'click');
* const result = clicks.pipe(
* concatMap(ev => interval(1000).pipe(take(4)))
* );
* result.subscribe(x => console.log(x));
*
* // Results in the following:
* // (results are not concurrent)
* // For every click on the "document" it will emit values 0 to 3 spaced
* // on a 1000ms interval
* // one click = 1000ms-> 0 -1000ms-> 1 -1000ms-> 2 -1000ms-> 3
* ```
*
* @see {@link concat}
* @see {@link concatAll}
* @see {@link concatMapTo}
* @see {@link exhaustMap}
* @see {@link mergeMap}
* @see {@link switchMap}
*
* @param {function(value: T, ?index: number): ObservableInput} project A function
* that, when applied to an item emitted by the source Observable, returns an
* Observable.
* @return A function that returns an Observable that emits the result of
* applying the projection function (and the optional deprecated
* `resultSelector`) to each item emitted by the source Observable and taking
* values from each projected inner Observable sequentially.
*/
export function concatMap<T, R, O extends ObservableInput<any>>(
project: (value: T, index: number) => O,
resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
): OperatorFunction<T, ObservedValueOf<O> | R> {
return isFunction(resultSelector) ? mergeMap(project, resultSelector, 1) : mergeMap(project, 1);
}