| 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); |
| } |
| _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 |
