64 lines
2.6 KiB
JavaScript
64 lines
2.6 KiB
JavaScript
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import { mergeMap as higherOrderMergeMap } from '../operators/mergeMap';
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/* tslint:enable:max-line-length */
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/**
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* Projects each source value to an Observable which is merged in the output
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* Observable.
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*
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* <span class="informal">Maps each value to an Observable, then flattens all of
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* these inner Observables using {@link mergeAll}.</span>
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*
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* <img src="./img/mergeMap.png" width="100%">
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*
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* Returns an Observable that emits items based on applying a function that you
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* supply to each item emitted by the source Observable, where that function
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* returns an Observable, and then merging those resulting Observables and
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* emitting the results of this merger.
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*
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* @example <caption>Map and flatten each letter to an Observable ticking every 1 second</caption>
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* var letters = Rx.Observable.of('a', 'b', 'c');
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* var result = letters.mergeMap(x =>
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* Rx.Observable.interval(1000).map(i => x+i)
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* );
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* result.subscribe(x => console.log(x));
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*
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* // Results in the following:
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* // a0
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* // b0
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* // c0
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* // a1
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* // b1
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* // c1
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* // continues to list a,b,c with respective ascending integers
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*
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* @see {@link concatMap}
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* @see {@link exhaustMap}
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* @see {@link merge}
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* @see {@link mergeAll}
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* @see {@link mergeMapTo}
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* @see {@link mergeScan}
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* @see {@link switchMap}
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*
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* @param {function(value: T, ?index: number): ObservableInput} project A function
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* that, when applied to an item emitted by the source Observable, returns an
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* 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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* @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of input
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* Observables being subscribed to concurrently.
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* @return {Observable} An Observable that emits the result of applying the
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* projection function (and the optional `resultSelector`) to each item emitted
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* by the source Observable and merging the results of the Observables obtained
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* from this transformation.
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* @method mergeMap
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* @owner Observable
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*/
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export function mergeMap(project, resultSelector, concurrent = Number.POSITIVE_INFINITY) {
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return higherOrderMergeMap(project, resultSelector, concurrent)(this);
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}
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//# sourceMappingURL=mergeMap.js.map
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