48 lines
2.3 KiB
JavaScript
48 lines
2.3 KiB
JavaScript
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import { switchMapTo as higherOrder } from '../operators/switchMapTo';
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/* tslint:enable:max-line-length */
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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 switch} 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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* <img src="./img/switchMapTo.png" width="100%">
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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 <caption>Rerun an interval Observable on every click event</caption>
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* var clicks = Rx.Observable.fromEvent(document, 'click');
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* var result = clicks.switchMapTo(Rx.Observable.interval(1000));
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* result.subscribe(x => console.log(x));
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*
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* @see {@link concatMapTo}
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* @see {@link switch}
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* @see {@link switchMap}
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* @see {@link mergeMapTo}
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*
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* @param {ObservableInput} innerObservable An Observable to replace each value from
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* the source Observable.
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* @param {function(outerValue: T, innerValue: I, outerIndex: number, innerIndex: number): any} [resultSelector]
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* A function to produce the value on the output Observable based on the values
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* and the indices of the source (outer) emission and the inner Observable
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* emission. The arguments passed to this function are:
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* - `outerValue`: the value that came from the source
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* - `innerValue`: the value that came from the projected Observable
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* - `outerIndex`: the "index" of the value that came from the source
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* - `innerIndex`: the "index" of the value from the projected Observable
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* @return {Observable} An Observable that emits items from the given
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* `innerObservable` (and optionally transformed through `resultSelector`) every
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* time a value is emitted on the source Observable, and taking only the values
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* from the most recently projected inner Observable.
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* @method switchMapTo
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* @owner Observable
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*/
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export function switchMapTo(innerObservable, resultSelector) {
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return higherOrder(innerObservable, resultSelector)(this);
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}
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//# sourceMappingURL=switchMapTo.js.map
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