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56 lines
2.5 KiB
56 lines
2.5 KiB
"use strict"; |
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var expand_1 = require('../operators/expand'); |
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/* tslint:enable:max-line-length */ |
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/** |
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* Recursively projects each source value to an Observable which is merged in |
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* the output Observable. |
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* |
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* <span class="informal">It's similar to {@link mergeMap}, but applies the |
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* projection function to every source value as well as every output value. |
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* It's recursive.</span> |
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* |
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* <img src="./img/expand.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. *Expand* will re-emit on the output |
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* Observable every source value. Then, each output value is given to the |
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* `project` function which returns an inner Observable to be merged on the |
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* output Observable. Those output values resulting from the projection are also |
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* given to the `project` function to produce new output values. This is how |
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* *expand* behaves recursively. |
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* |
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* @example <caption>Start emitting the powers of two on every click, at most 10 of them</caption> |
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* var clicks = Rx.Observable.fromEvent(document, 'click'); |
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* var powersOfTwo = clicks |
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* .mapTo(1) |
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* .expand(x => Rx.Observable.of(2 * x).delay(1000)) |
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* .take(10); |
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* powersOfTwo.subscribe(x => console.log(x)); |
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* |
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* @see {@link mergeMap} |
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* @see {@link mergeScan} |
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* |
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* @param {function(value: T, index: number) => Observable} project A function |
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* that, when applied to an item emitted by the source or the output Observable, |
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* returns an 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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* @param {Scheduler} [scheduler=null] The IScheduler to use for subscribing to |
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* each projected inner Observable. |
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* @return {Observable} An Observable that emits the source values and also |
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* result of applying the projection function to each value emitted on the |
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* output Observable and and merging the results of the Observables obtained |
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* from this transformation. |
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* @method expand |
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* @owner Observable |
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*/ |
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function expand(project, concurrent, scheduler) { |
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if (concurrent === void 0) { concurrent = Number.POSITIVE_INFINITY; } |
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if (scheduler === void 0) { scheduler = undefined; } |
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concurrent = (concurrent || 0) < 1 ? Number.POSITIVE_INFINITY : concurrent; |
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return expand_1.expand(project, concurrent, scheduler)(this); |
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} |
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exports.expand = expand; |
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//# sourceMappingURL=expand.js.map
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