65 lines
3.0 KiB
Plaintext
65 lines
3.0 KiB
Plaintext
import { switchMap } from './switchMap';
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import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
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import { isFunction } from '../util/isFunction';
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/** @deprecated Will be removed in v9. Use {@link switchMap} instead: `switchMap(() => result)` */
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export function switchMapTo<O extends ObservableInput<unknown>>(observable: O): OperatorFunction<unknown, ObservedValueOf<O>>;
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/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
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export function switchMapTo<O extends ObservableInput<unknown>>(
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observable: O,
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resultSelector: undefined
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): OperatorFunction<unknown, ObservedValueOf<O>>;
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/** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
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export function switchMapTo<T, R, O extends ObservableInput<unknown>>(
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observable: O,
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resultSelector: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
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): OperatorFunction<T, R>;
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/**
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* Projects each source value to the same Observable which is flattened multiple
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* times with {@link switchMap} in the output Observable.
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*
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* <span class="informal">It's like {@link switchMap}, but maps each value
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* always to the same inner Observable.</span>
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*
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* 
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*
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* Maps each source value to the given Observable `innerObservable` regardless
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* of the source value, and then flattens those resulting Observables into one
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* single Observable, which is the output Observable. The output Observables
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* emits values only from the most recently emitted instance of
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* `innerObservable`.
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*
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* ## Example
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*
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* Restart an interval Observable on every click event
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*
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* ```ts
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* import { fromEvent, switchMapTo, interval } from 'rxjs';
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*
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* const clicks = fromEvent(document, 'click');
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* const result = clicks.pipe(switchMapTo(interval(1000)));
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* result.subscribe(x => console.log(x));
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* ```
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*
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* @see {@link concatMapTo}
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* @see {@link switchAll}
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* @see {@link switchMap}
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* @see {@link mergeMapTo}
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*
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* @param innerObservable An `ObservableInput` to replace each value from the
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* source Observable.
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* @return A function that returns an Observable that emits items from the
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* given `innerObservable` (and optionally transformed through the deprecated
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* `resultSelector`) every time a value is emitted on the source Observable,
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* and taking only the values from the most recently projected inner
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* Observable.
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* @deprecated Will be removed in v9. Use {@link switchMap} instead: `switchMap(() => result)`
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*/
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export function switchMapTo<T, R, O extends ObservableInput<unknown>>(
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innerObservable: O,
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resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
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): OperatorFunction<T, ObservedValueOf<O> | R> {
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return isFunction(resultSelector) ? switchMap(() => innerObservable, resultSelector) : switchMap(() => innerObservable);
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}
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