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- import { Observable } from '../Observable';
- import { EmptyObservable } from './EmptyObservable';
- import { isArray } from '../util/isArray';
- import { subscribeToResult } from '../util/subscribeToResult';
- import { OuterSubscriber } from '../OuterSubscriber';
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @extends {Ignored}
- * @hide true
- */
- export class ForkJoinObservable extends Observable {
- constructor(sources, resultSelector) {
- super();
- this.sources = sources;
- this.resultSelector = resultSelector;
- }
- /* tslint:enable:max-line-length */
- /**
- * Joins last values emitted by passed Observables.
- *
- * <span class="informal">Wait for Observables to complete and then combine last values they emitted.</span>
- *
- * <img src="./img/forkJoin.png" width="100%">
- *
- * `forkJoin` is an operator that takes any number of Observables which can be passed either as an array
- * or directly as arguments. If no input Observables are provided, resulting stream will complete
- * immediately.
- *
- * `forkJoin` will wait for all passed Observables to complete and then it will emit an array with last
- * values from corresponding Observables. So if you pass `n` Observables to the operator, resulting
- * array will have `n` values, where first value is the last thing emitted by the first Observable,
- * second value is the last thing emitted by the second Observable and so on. That means `forkJoin` will
- * not emit more than once and it will complete after that. If you need to emit combined values not only
- * at the end of lifecycle of passed Observables, but also throughout it, try out {@link combineLatest}
- * or {@link zip} instead.
- *
- * In order for resulting array to have the same length as the number of input Observables, whenever any of
- * that Observables completes without emitting any value, `forkJoin` will complete at that moment as well
- * and it will not emit anything either, even if it already has some last values from other Observables.
- * Conversely, if there is an Observable that never completes, `forkJoin` will never complete as well,
- * unless at any point some other Observable completes without emitting value, which brings us back to
- * the previous case. Overall, in order for `forkJoin` to emit a value, all Observables passed as arguments
- * have to emit something at least once and complete.
- *
- * If any input Observable errors at some point, `forkJoin` will error as well and all other Observables
- * will be immediately unsubscribed.
- *
- * Optionally `forkJoin` accepts project function, that will be called with values which normally
- * would land in emitted array. Whatever is returned by project function, will appear in output
- * Observable instead. This means that default project can be thought of as a function that takes
- * all its arguments and puts them into an array. Note that project function will be called only
- * when output Observable is supposed to emit a result.
- *
- * @example <caption>Use forkJoin with operator emitting immediately</caption>
- * const observable = Rx.Observable.forkJoin(
- * Rx.Observable.of(1, 2, 3, 4),
- * Rx.Observable.of(5, 6, 7, 8)
- * );
- * observable.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('This is how it ends!')
- * );
- *
- * // Logs:
- * // [4, 8]
- * // "This is how it ends!"
- *
- *
- * @example <caption>Use forkJoin with operator emitting after some time</caption>
- * const observable = Rx.Observable.forkJoin(
- * Rx.Observable.interval(1000).take(3), // emit 0, 1, 2 every second and complete
- * Rx.Observable.interval(500).take(4) // emit 0, 1, 2, 3 every half a second and complete
- * );
- * observable.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('This is how it ends!')
- * );
- *
- * // Logs:
- * // [2, 3] after 3 seconds
- * // "This is how it ends!" immediately after
- *
- *
- * @example <caption>Use forkJoin with project function</caption>
- * const observable = Rx.Observable.forkJoin(
- * Rx.Observable.interval(1000).take(3), // emit 0, 1, 2 every second and complete
- * Rx.Observable.interval(500).take(4), // emit 0, 1, 2, 3 every half a second and complete
- * (n, m) => n + m
- * );
- * observable.subscribe(
- * value => console.log(value),
- * err => {},
- * () => console.log('This is how it ends!')
- * );
- *
- * // Logs:
- * // 5 after 3 seconds
- * // "This is how it ends!" immediately after
- *
- * @see {@link combineLatest}
- * @see {@link zip}
- *
- * @param {...SubscribableOrPromise} sources Any number of Observables provided either as an array or as an arguments
- * passed directly to the operator.
- * @param {function} [project] Function that takes values emitted by input Observables and returns value
- * that will appear in resulting Observable instead of default array.
- * @return {Observable} Observable emitting either an array of last values emitted by passed Observables
- * or value from project function.
- * @static true
- * @name forkJoin
- * @owner Observable
- */
- static create(...sources) {
- if (sources === null || arguments.length === 0) {
- return new EmptyObservable();
- }
- let resultSelector = null;
- if (typeof sources[sources.length - 1] === 'function') {
- resultSelector = sources.pop();
- }
- // if the first and only other argument besides the resultSelector is an array
- // assume it's been called with `forkJoin([obs1, obs2, obs3], resultSelector)`
- if (sources.length === 1 && isArray(sources[0])) {
- sources = sources[0];
- }
- if (sources.length === 0) {
- return new EmptyObservable();
- }
- return new ForkJoinObservable(sources, resultSelector);
- }
- /** @deprecated internal use only */ _subscribe(subscriber) {
- return new ForkJoinSubscriber(subscriber, this.sources, this.resultSelector);
- }
- }
- /**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
- class ForkJoinSubscriber extends OuterSubscriber {
- constructor(destination, sources, resultSelector) {
- super(destination);
- this.sources = sources;
- this.resultSelector = resultSelector;
- this.completed = 0;
- this.haveValues = 0;
- const len = sources.length;
- this.total = len;
- this.values = new Array(len);
- for (let i = 0; i < len; i++) {
- const source = sources[i];
- const innerSubscription = subscribeToResult(this, source, null, i);
- if (innerSubscription) {
- innerSubscription.outerIndex = i;
- this.add(innerSubscription);
- }
- }
- }
- notifyNext(outerValue, innerValue, outerIndex, innerIndex, innerSub) {
- this.values[outerIndex] = innerValue;
- if (!innerSub._hasValue) {
- innerSub._hasValue = true;
- this.haveValues++;
- }
- }
- notifyComplete(innerSub) {
- const destination = this.destination;
- const { haveValues, resultSelector, values } = this;
- const len = values.length;
- if (!innerSub._hasValue) {
- destination.complete();
- return;
- }
- this.completed++;
- if (this.completed !== len) {
- return;
- }
- if (haveValues === len) {
- const value = resultSelector ? resultSelector.apply(this, values) : values;
- destination.next(value);
- }
- destination.complete();
- }
- }
- //# sourceMappingURL=ForkJoinObservable.js.map
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