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138 lines
5.8 KiB
138 lines
5.8 KiB
"use strict"; |
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var __extends = (this && this.__extends) || function (d, b) { |
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for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; |
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function __() { this.constructor = d; } |
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d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __()); |
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}; |
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var OuterSubscriber_1 = require('../OuterSubscriber'); |
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var subscribeToResult_1 = require('../util/subscribeToResult'); |
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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 only if the previous projected Observable has completed. |
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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 exhaust}.</span> |
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* |
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* <img src="./img/exhaustMap.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 (so-called "inner") Observable. When it projects a source value to |
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* an Observable, the output Observable begins emitting the items emitted by |
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* that projected Observable. However, `exhaustMap` ignores every new projected |
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* Observable if the previous projected Observable has not yet completed. Once |
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* that one completes, it will accept and flatten the next projected Observable |
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* and repeat this process. |
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* |
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* @example <caption>Run a finite timer for each click, only if there is no currently active timer</caption> |
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* var clicks = Rx.Observable.fromEvent(document, 'click'); |
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* var result = clicks.exhaustMap((ev) => Rx.Observable.interval(1000).take(5)); |
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* result.subscribe(x => console.log(x)); |
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* |
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* @see {@link concatMap} |
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* @see {@link exhaust} |
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* @see {@link mergeMap} |
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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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* @return {Observable} An Observable containing projected Observables |
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* of each item of the source, ignoring projected Observables that start before |
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* their preceding Observable has completed. |
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* @method exhaustMap |
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* @owner Observable |
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*/ |
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function exhaustMap(project, resultSelector) { |
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return function (source) { return source.lift(new SwitchFirstMapOperator(project, resultSelector)); }; |
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} |
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exports.exhaustMap = exhaustMap; |
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var SwitchFirstMapOperator = (function () { |
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function SwitchFirstMapOperator(project, resultSelector) { |
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this.project = project; |
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this.resultSelector = resultSelector; |
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} |
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SwitchFirstMapOperator.prototype.call = function (subscriber, source) { |
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return source.subscribe(new SwitchFirstMapSubscriber(subscriber, this.project, this.resultSelector)); |
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}; |
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return SwitchFirstMapOperator; |
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}()); |
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/** |
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* We need this JSDoc comment for affecting ESDoc. |
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* @ignore |
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* @extends {Ignored} |
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*/ |
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var SwitchFirstMapSubscriber = (function (_super) { |
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__extends(SwitchFirstMapSubscriber, _super); |
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function SwitchFirstMapSubscriber(destination, project, resultSelector) { |
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_super.call(this, destination); |
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this.project = project; |
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this.resultSelector = resultSelector; |
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this.hasSubscription = false; |
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this.hasCompleted = false; |
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this.index = 0; |
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} |
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SwitchFirstMapSubscriber.prototype._next = function (value) { |
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if (!this.hasSubscription) { |
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this.tryNext(value); |
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} |
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}; |
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SwitchFirstMapSubscriber.prototype.tryNext = function (value) { |
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var index = this.index++; |
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var destination = this.destination; |
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try { |
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var result = this.project(value, index); |
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this.hasSubscription = true; |
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this.add(subscribeToResult_1.subscribeToResult(this, result, value, index)); |
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} |
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catch (err) { |
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destination.error(err); |
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} |
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}; |
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SwitchFirstMapSubscriber.prototype._complete = function () { |
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this.hasCompleted = true; |
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if (!this.hasSubscription) { |
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this.destination.complete(); |
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} |
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}; |
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SwitchFirstMapSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
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var _a = this, resultSelector = _a.resultSelector, destination = _a.destination; |
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if (resultSelector) { |
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this.trySelectResult(outerValue, innerValue, outerIndex, innerIndex); |
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} |
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else { |
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destination.next(innerValue); |
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} |
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}; |
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SwitchFirstMapSubscriber.prototype.trySelectResult = function (outerValue, innerValue, outerIndex, innerIndex) { |
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var _a = this, resultSelector = _a.resultSelector, destination = _a.destination; |
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try { |
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var result = resultSelector(outerValue, innerValue, outerIndex, innerIndex); |
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destination.next(result); |
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} |
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catch (err) { |
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destination.error(err); |
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} |
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}; |
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SwitchFirstMapSubscriber.prototype.notifyError = function (err) { |
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this.destination.error(err); |
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}; |
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SwitchFirstMapSubscriber.prototype.notifyComplete = function (innerSub) { |
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this.remove(innerSub); |
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this.hasSubscription = false; |
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if (this.hasCompleted) { |
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this.destination.complete(); |
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} |
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}; |
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return SwitchFirstMapSubscriber; |
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}(OuterSubscriber_1.OuterSubscriber)); |
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//# sourceMappingURL=exhaustMap.js.map
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