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- "use strict";
- var __extends = (this && this.__extends) || function (d, b) {
- for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
- function __() { this.constructor = d; }
- d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
- };
- var OuterSubscriber_1 = require('../OuterSubscriber');
- var subscribeToResult_1 = require('../util/subscribeToResult');
- /* tslint:enable:max-line-length */
- /**
- * Projects each source value to an Observable which is merged in the output
- * Observable, emitting values only from the most recently projected Observable.
- *
- * <span class="informal">Maps each value to an Observable, then flattens all of
- * these inner Observables using {@link switch}.</span>
- *
- * <img src="./img/switchMap.png" width="100%">
- *
- * Returns an Observable that emits items based on applying a function that you
- * supply to each item emitted by the source Observable, where that function
- * returns an (so-called "inner") Observable. Each time it observes one of these
- * inner Observables, the output Observable begins emitting the items emitted by
- * that inner Observable. When a new inner Observable is emitted, `switchMap`
- * stops emitting items from the earlier-emitted inner Observable and begins
- * emitting items from the new one. It continues to behave like this for
- * subsequent inner Observables.
- *
- * @example <caption>Rerun an interval Observable on every click event</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var result = clicks.switchMap((ev) => Rx.Observable.interval(1000));
- * result.subscribe(x => console.log(x));
- *
- * @see {@link concatMap}
- * @see {@link exhaustMap}
- * @see {@link mergeMap}
- * @see {@link switch}
- * @see {@link switchMapTo}
- *
- * @param {function(value: T, ?index: number): ObservableInput} project A function
- * that, when applied to an item emitted by the source Observable, returns an
- * Observable.
- * @param {function(outerValue: T, innerValue: I, outerIndex: number, innerIndex: number): any} [resultSelector]
- * A function to produce the value on the output Observable based on the values
- * and the indices of the source (outer) emission and the inner Observable
- * emission. The arguments passed to this function are:
- * - `outerValue`: the value that came from the source
- * - `innerValue`: the value that came from the projected Observable
- * - `outerIndex`: the "index" of the value that came from the source
- * - `innerIndex`: the "index" of the value from the projected Observable
- * @return {Observable} An Observable that emits the result of applying the
- * projection function (and the optional `resultSelector`) to each item emitted
- * by the source Observable and taking only the values from the most recently
- * projected inner Observable.
- * @method switchMap
- * @owner Observable
- */
- function switchMap(project, resultSelector) {
- return function switchMapOperatorFunction(source) {
- return source.lift(new SwitchMapOperator(project, resultSelector));
- };
- }
- exports.switchMap = switchMap;
- var SwitchMapOperator = (function () {
- function SwitchMapOperator(project, resultSelector) {
- this.project = project;
- this.resultSelector = resultSelector;
- }
- SwitchMapOperator.prototype.call = function (subscriber, source) {
- return source.subscribe(new SwitchMapSubscriber(subscriber, this.project, this.resultSelector));
- };
- return SwitchMapOperator;
- }());
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- var SwitchMapSubscriber = (function (_super) {
- __extends(SwitchMapSubscriber, _super);
- function SwitchMapSubscriber(destination, project, resultSelector) {
- _super.call(this, destination);
- this.project = project;
- this.resultSelector = resultSelector;
- this.index = 0;
- }
- SwitchMapSubscriber.prototype._next = function (value) {
- var result;
- var index = this.index++;
- try {
- result = this.project(value, index);
- }
- catch (error) {
- this.destination.error(error);
- return;
- }
- this._innerSub(result, value, index);
- };
- SwitchMapSubscriber.prototype._innerSub = function (result, value, index) {
- var innerSubscription = this.innerSubscription;
- if (innerSubscription) {
- innerSubscription.unsubscribe();
- }
- this.add(this.innerSubscription = subscribeToResult_1.subscribeToResult(this, result, value, index));
- };
- SwitchMapSubscriber.prototype._complete = function () {
- var innerSubscription = this.innerSubscription;
- if (!innerSubscription || innerSubscription.closed) {
- _super.prototype._complete.call(this);
- }
- };
- /** @deprecated internal use only */ SwitchMapSubscriber.prototype._unsubscribe = function () {
- this.innerSubscription = null;
- };
- SwitchMapSubscriber.prototype.notifyComplete = function (innerSub) {
- this.remove(innerSub);
- this.innerSubscription = null;
- if (this.isStopped) {
- _super.prototype._complete.call(this);
- }
- };
- SwitchMapSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
- if (this.resultSelector) {
- this._tryNotifyNext(outerValue, innerValue, outerIndex, innerIndex);
- }
- else {
- this.destination.next(innerValue);
- }
- };
- SwitchMapSubscriber.prototype._tryNotifyNext = function (outerValue, innerValue, outerIndex, innerIndex) {
- var result;
- try {
- result = this.resultSelector(outerValue, innerValue, outerIndex, innerIndex);
- }
- catch (err) {
- this.destination.error(err);
- return;
- }
- this.destination.next(result);
- };
- return SwitchMapSubscriber;
- }(OuterSubscriber_1.OuterSubscriber));
- //# sourceMappingURL=switchMap.js.map
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