144 lines
5.9 KiB
JavaScript
Executable File
144 lines
5.9 KiB
JavaScript
Executable File
/** PURE_IMPORTS_START .._OuterSubscriber,.._util_subscribeToResult PURE_IMPORTS_END */
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var __extends = (this && this.__extends) || function (d, b) {
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for (var p in b)
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if (b.hasOwnProperty(p))
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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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import { OuterSubscriber } from '../OuterSubscriber';
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import { subscribeToResult } from '../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, emitting values only from the most recently projected 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 switch}.</span>
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*
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* <img src="./img/switchMap.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. Each time it observes one of these
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* inner Observables, the output Observable begins emitting the items emitted by
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* that inner Observable. When a new inner Observable is emitted, `switchMap`
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* stops emitting items from the earlier-emitted inner Observable and begins
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* emitting items from the new one. It continues to behave like this for
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* subsequent inner Observables.
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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.switchMap((ev) => Rx.Observable.interval(1000));
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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 exhaustMap}
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* @see {@link mergeMap}
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* @see {@link switch}
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* @see {@link switchMapTo}
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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 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 taking only the values from the most recently
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* projected inner Observable.
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* @method switchMap
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* @owner Observable
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*/
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export function switchMap(project, resultSelector) {
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return function switchMapOperatorFunction(source) {
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return source.lift(new SwitchMapOperator(project, resultSelector));
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};
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}
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var SwitchMapOperator = /*@__PURE__*/ (/*@__PURE__*/ function () {
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function SwitchMapOperator(project, resultSelector) {
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this.project = project;
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this.resultSelector = resultSelector;
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}
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SwitchMapOperator.prototype.call = function (subscriber, source) {
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return source.subscribe(new SwitchMapSubscriber(subscriber, this.project, this.resultSelector));
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};
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return SwitchMapOperator;
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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 SwitchMapSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
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__extends(SwitchMapSubscriber, _super);
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function SwitchMapSubscriber(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.index = 0;
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}
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SwitchMapSubscriber.prototype._next = function (value) {
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var result;
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var index = this.index++;
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try {
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result = this.project(value, index);
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}
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catch (error) {
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this.destination.error(error);
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return;
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}
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this._innerSub(result, value, index);
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};
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SwitchMapSubscriber.prototype._innerSub = function (result, value, index) {
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var innerSubscription = this.innerSubscription;
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if (innerSubscription) {
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innerSubscription.unsubscribe();
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}
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this.add(this.innerSubscription = subscribeToResult(this, result, value, index));
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};
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SwitchMapSubscriber.prototype._complete = function () {
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var innerSubscription = this.innerSubscription;
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if (!innerSubscription || innerSubscription.closed) {
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_super.prototype._complete.call(this);
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}
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};
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/** @deprecated internal use only */ SwitchMapSubscriber.prototype._unsubscribe = function () {
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this.innerSubscription = null;
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};
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SwitchMapSubscriber.prototype.notifyComplete = function (innerSub) {
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this.remove(innerSub);
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this.innerSubscription = null;
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if (this.isStopped) {
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_super.prototype._complete.call(this);
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}
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};
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SwitchMapSubscriber.prototype.notifyNext = function (outerValue, innerValue, outerIndex, innerIndex, innerSub) {
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if (this.resultSelector) {
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this._tryNotifyNext(outerValue, innerValue, outerIndex, innerIndex);
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}
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else {
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this.destination.next(innerValue);
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}
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};
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SwitchMapSubscriber.prototype._tryNotifyNext = function (outerValue, innerValue, outerIndex, innerIndex) {
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var result;
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try {
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result = this.resultSelector(outerValue, innerValue, outerIndex, innerIndex);
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}
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catch (err) {
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this.destination.error(err);
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return;
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}
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this.destination.next(result);
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};
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return SwitchMapSubscriber;
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}(OuterSubscriber));
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//# sourceMappingURL=switchMap.js.map
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