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- import { OuterSubscriber } from '../OuterSubscriber';
- import { subscribeToResult } from '../util/subscribeToResult';
- /* tslint:enable:max-line-length */
- /**
- * Projects each source value to an Observable which is merged in the output
- * Observable only if the previous projected Observable has completed.
- *
- * <span class="informal">Maps each value to an Observable, then flattens all of
- * these inner Observables using {@link exhaust}.</span>
- *
- * <img src="./img/exhaustMap.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. When it projects a source value to
- * an Observable, the output Observable begins emitting the items emitted by
- * that projected Observable. However, `exhaustMap` ignores every new projected
- * Observable if the previous projected Observable has not yet completed. Once
- * that one completes, it will accept and flatten the next projected Observable
- * and repeat this process.
- *
- * @example <caption>Run a finite timer for each click, only if there is no currently active timer</caption>
- * var clicks = Rx.Observable.fromEvent(document, 'click');
- * var result = clicks.exhaustMap((ev) => Rx.Observable.interval(1000).take(5));
- * result.subscribe(x => console.log(x));
- *
- * @see {@link concatMap}
- * @see {@link exhaust}
- * @see {@link mergeMap}
- * @see {@link switchMap}
- *
- * @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 containing projected Observables
- * of each item of the source, ignoring projected Observables that start before
- * their preceding Observable has completed.
- * @method exhaustMap
- * @owner Observable
- */
- export function exhaustMap(project, resultSelector) {
- return (source) => source.lift(new SwitchFirstMapOperator(project, resultSelector));
- }
- class SwitchFirstMapOperator {
- constructor(project, resultSelector) {
- this.project = project;
- this.resultSelector = resultSelector;
- }
- call(subscriber, source) {
- return source.subscribe(new SwitchFirstMapSubscriber(subscriber, this.project, this.resultSelector));
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class SwitchFirstMapSubscriber extends OuterSubscriber {
- constructor(destination, project, resultSelector) {
- super(destination);
- this.project = project;
- this.resultSelector = resultSelector;
- this.hasSubscription = false;
- this.hasCompleted = false;
- this.index = 0;
- }
- _next(value) {
- if (!this.hasSubscription) {
- this.tryNext(value);
- }
- }
- tryNext(value) {
- const index = this.index++;
- const destination = this.destination;
- try {
- const result = this.project(value, index);
- this.hasSubscription = true;
- this.add(subscribeToResult(this, result, value, index));
- }
- catch (err) {
- destination.error(err);
- }
- }
- _complete() {
- this.hasCompleted = true;
- if (!this.hasSubscription) {
- this.destination.complete();
- }
- }
- notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
- const { resultSelector, destination } = this;
- if (resultSelector) {
- this.trySelectResult(outerValue, innerValue, outerIndex, innerIndex);
- }
- else {
- destination.next(innerValue);
- }
- }
- trySelectResult(outerValue, innerValue, outerIndex, innerIndex) {
- const { resultSelector, destination } = this;
- try {
- const result = resultSelector(outerValue, innerValue, outerIndex, innerIndex);
- destination.next(result);
- }
- catch (err) {
- destination.error(err);
- }
- }
- notifyError(err) {
- this.destination.error(err);
- }
- notifyComplete(innerSub) {
- this.remove(innerSub);
- this.hasSubscription = false;
- if (this.hasCompleted) {
- this.destination.complete();
- }
- }
- }
- //# sourceMappingURL=exhaustMap.js.map
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