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- import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
- import { map } from './map';
- import { innerFrom } from '../observable/innerFrom';
- import { operate } from '../util/lift';
- import { mergeInternals } from './mergeInternals';
- import { isFunction } from '../util/isFunction';
- /* tslint:disable:max-line-length */
- export function mergeMap<T, O extends ObservableInput<any>>(
- project: (value: T, index: number) => O,
- concurrent?: number
- ): 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 mergeMap<T, O extends ObservableInput<any>>(
- project: (value: T, index: number) => O,
- resultSelector: undefined,
- concurrent?: number
- ): 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 mergeMap<T, R, O extends ObservableInput<any>>(
- project: (value: T, index: number) => 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 an Observable which is merged in the output
- * Observable.
- *
- * <span class="informal">Maps each value to an Observable, then flattens all of
- * these inner Observables using {@link mergeAll}.</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 Observable, and then merging those resulting Observables and
- * emitting the results of this merger.
- *
- * ## Example
- *
- * Map and flatten each letter to an Observable ticking every 1 second
- *
- * ```ts
- * import { of, mergeMap, interval, map } from 'rxjs';
- *
- * const letters = of('a', 'b', 'c');
- * const result = letters.pipe(
- * mergeMap(x => interval(1000).pipe(map(i => x + i)))
- * );
- *
- * result.subscribe(x => console.log(x));
- *
- * // Results in the following:
- * // a0
- * // b0
- * // c0
- * // a1
- * // b1
- * // c1
- * // continues to list a, b, c every second with respective ascending integers
- * ```
- *
- * @see {@link concatMap}
- * @see {@link exhaustMap}
- * @see {@link merge}
- * @see {@link mergeAll}
- * @see {@link mergeMapTo}
- * @see {@link mergeScan}
- * @see {@link switchMap}
- *
- * @param project A function that, when applied to an item emitted by the source
- * Observable, returns an Observable.
- * @param concurrent Maximum number of `ObservableInput`s being subscribed to concurrently.
- * @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 merging
- * the results of the Observables obtained from this transformation.
- */
- export function mergeMap<T, R, O extends ObservableInput<any>>(
- project: (value: T, index: number) => O,
- resultSelector?: ((outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R) | number,
- concurrent: number = Infinity
- ): OperatorFunction<T, ObservedValueOf<O> | R> {
- if (isFunction(resultSelector)) {
- // DEPRECATED PATH
- return mergeMap((a, i) => map((b: any, ii: number) => resultSelector(a, b, i, ii))(innerFrom(project(a, i))), concurrent);
- } else if (typeof resultSelector === 'number') {
- concurrent = resultSelector;
- }
- return operate((source, subscriber) => mergeInternals(source, subscriber, project, concurrent));
- }
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