| import { subscribeToResult } from '../util/subscribeToResult'; |
| import { OuterSubscriber } from '../OuterSubscriber'; |
| /* tslint:enable:max-line-length */ |
| /** |
| * Projects each source value to an Observable which is merged in the output |
| * Observable. |
| * |
| * <span class="informal">Maps each value to an Observable, then flattens all of |
| * these inner Observables using {@link mergeAll}.</span> |
| * |
| * <img src="./img/mergeMap.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 Observable, and then merging those resulting Observables and |
| * emitting the results of this merger. |
| * |
| * @example <caption>Map and flatten each letter to an Observable ticking every 1 second</caption> |
| * var letters = Rx.Observable.of('a', 'b', 'c'); |
| * var result = letters.mergeMap(x => |
| * Rx.Observable.interval(1000).map(i => x+i) |
| * ); |
| * result.subscribe(x => console.log(x)); |
| * |
| * // Results in the following: |
| * // a0 |
| * // b0 |
| * // c0 |
| * // a1 |
| * // b1 |
| * // c1 |
| * // continues to list a,b,c with respective ascending integers |
| * |
| * @see {@link concatMap} |
| * @see {@link exhaustMap} |
| * @see {@link merge} |
| * @see {@link mergeAll} |
| * @see {@link mergeMapTo} |
| * @see {@link mergeScan} |
| * @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 |
| * @param {number} [concurrent=Number.POSITIVE_INFINITY] Maximum number of input |
| * Observables being subscribed to concurrently. |
| * @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 merging the results of the Observables obtained |
| * from this transformation. |
| * @method mergeMap |
| * @owner Observable |
| */ |
| export function mergeMap(project, resultSelector, concurrent = Number.POSITIVE_INFINITY) { |
| return function mergeMapOperatorFunction(source) { |
| if (typeof resultSelector === 'number') { |
| concurrent = resultSelector; |
| resultSelector = null; |
| } |
| return source.lift(new MergeMapOperator(project, resultSelector, concurrent)); |
| }; |
| } |
| export class MergeMapOperator { |
| constructor(project, resultSelector, concurrent = Number.POSITIVE_INFINITY) { |
| this.project = project; |
| this.resultSelector = resultSelector; |
| this.concurrent = concurrent; |
| } |
| call(observer, source) { |
| return source.subscribe(new MergeMapSubscriber(observer, this.project, this.resultSelector, this.concurrent)); |
| } |
| } |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| export class MergeMapSubscriber extends OuterSubscriber { |
| constructor(destination, project, resultSelector, concurrent = Number.POSITIVE_INFINITY) { |
| super(destination); |
| this.project = project; |
| this.resultSelector = resultSelector; |
| this.concurrent = concurrent; |
| this.hasCompleted = false; |
| this.buffer = []; |
| this.active = 0; |
| this.index = 0; |
| } |
| _next(value) { |
| if (this.active < this.concurrent) { |
| this._tryNext(value); |
| } |
| else { |
| this.buffer.push(value); |
| } |
| } |
| _tryNext(value) { |
| let result; |
| const index = this.index++; |
| try { |
| result = this.project(value, index); |
| } |
| catch (err) { |
| this.destination.error(err); |
| return; |
| } |
| this.active++; |
| this._innerSub(result, value, index); |
| } |
| _innerSub(ish, value, index) { |
| this.add(subscribeToResult(this, ish, value, index)); |
| } |
| _complete() { |
| this.hasCompleted = true; |
| if (this.active === 0 && this.buffer.length === 0) { |
| this.destination.complete(); |
| } |
| } |
| notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) { |
| if (this.resultSelector) { |
| this._notifyResultSelector(outerValue, innerValue, outerIndex, innerIndex); |
| } |
| else { |
| this.destination.next(innerValue); |
| } |
| } |
| _notifyResultSelector(outerValue, innerValue, outerIndex, innerIndex) { |
| let result; |
| try { |
| result = this.resultSelector(outerValue, innerValue, outerIndex, innerIndex); |
| } |
| catch (err) { |
| this.destination.error(err); |
| return; |
| } |
| this.destination.next(result); |
| } |
| notifyComplete(innerSub) { |
| const buffer = this.buffer; |
| this.remove(innerSub); |
| this.active--; |
| if (buffer.length > 0) { |
| this._next(buffer.shift()); |
| } |
| else if (this.active === 0 && this.hasCompleted) { |
| this.destination.complete(); |
| } |
| } |
| } |
| //# sourceMappingURL=mergeMap.js.map |