123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158 |
- 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
|