| 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 |