import { Observable } from '../Observable';
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import { ObservedValueOf, ObservableInputTuple, ObservableInput } from '../types';
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import { argsArgArrayOrObject } from '../util/argsArgArrayOrObject';
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import { innerFrom } from './innerFrom';
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import { popResultSelector } from '../util/args';
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import { createOperatorSubscriber } from '../operators/OperatorSubscriber';
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import { mapOneOrManyArgs } from '../util/mapOneOrManyArgs';
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import { createObject } from '../util/createObject';
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import { AnyCatcher } from '../AnyCatcher';
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// forkJoin(any)
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// We put this first because we need to catch cases where the user has supplied
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// _exactly `any`_ as the argument. Since `any` literally matches _anything_,
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// we don't want it to randomly hit one of the other type signatures below,
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// as we have no idea at build-time what type we should be returning when given an any.
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/**
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* You have passed `any` here, we can't figure out if it is
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* an array or an object, so you're getting `unknown`. Use better types.
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* @param arg Something typed as `any`
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*/
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export function forkJoin<T extends AnyCatcher>(arg: T): Observable<unknown>;
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// forkJoin(null | undefined)
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export function forkJoin(scheduler: null | undefined): Observable<never>;
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// forkJoin([a, b, c])
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export function forkJoin(sources: readonly []): Observable<never>;
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export function forkJoin<A extends readonly unknown[]>(sources: readonly [...ObservableInputTuple<A>]): Observable<A>;
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export function forkJoin<A extends readonly unknown[], R>(
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sources: readonly [...ObservableInputTuple<A>],
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resultSelector: (...values: A) => R
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): Observable<R>;
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// forkJoin(a, b, c)
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/** @deprecated Pass an array of sources instead. The rest-parameters signature will be removed in v8. Details: https://rxjs.dev/deprecations/array-argument */
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export function forkJoin<A extends readonly unknown[]>(...sources: [...ObservableInputTuple<A>]): Observable<A>;
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/** @deprecated Pass an array of sources instead. The rest-parameters signature will be removed in v8. Details: https://rxjs.dev/deprecations/array-argument */
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export function forkJoin<A extends readonly unknown[], R>(
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...sourcesAndResultSelector: [...ObservableInputTuple<A>, (...values: A) => R]
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): Observable<R>;
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// forkJoin({a, b, c})
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export function forkJoin(sourcesObject: { [K in any]: never }): Observable<never>;
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export function forkJoin<T extends Record<string, ObservableInput<any>>>(
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sourcesObject: T
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): Observable<{ [K in keyof T]: ObservedValueOf<T[K]> }>;
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/**
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* Accepts an `Array` of {@link ObservableInput} or a dictionary `Object` of {@link ObservableInput} and returns
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* an {@link Observable} that emits either an array of values in the exact same order as the passed array,
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* or a dictionary of values in the same shape as the passed dictionary.
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*
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* <span class="informal">Wait for Observables to complete and then combine last values they emitted;
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* complete immediately if an empty array is passed.</span>
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*
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* 
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*
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* `forkJoin` is an operator that takes any number of input observables which can be passed either as an array
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* or a dictionary of input observables. If no input observables are provided (e.g. an empty array is passed),
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* then the resulting stream will complete immediately.
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*
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* `forkJoin` will wait for all passed observables to emit and complete and then it will emit an array or an object with last
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* values from corresponding observables.
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*
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* If you pass an array of `n` observables to the operator, then the resulting
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* array will have `n` values, where the first value is the last one emitted by the first observable,
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* second value is the last one emitted by the second observable and so on.
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*
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* If you pass a dictionary of observables to the operator, then the resulting
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* objects will have the same keys as the dictionary passed, with their last values they have emitted
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* located at the corresponding key.
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*
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* That means `forkJoin` will not emit more than once and it will complete after that. If you need to emit combined
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* values not only at the end of the lifecycle of passed observables, but also throughout it, try out {@link combineLatest}
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* or {@link zip} instead.
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*
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* In order for the resulting array to have the same length as the number of input observables, whenever any of
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* the given observables completes without emitting any value, `forkJoin` will complete at that moment as well
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* and it will not emit anything either, even if it already has some last values from other observables.
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* Conversely, if there is an observable that never completes, `forkJoin` will never complete either,
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* unless at any point some other observable completes without emitting a value, which brings us back to
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* the previous case. Overall, in order for `forkJoin` to emit a value, all given observables
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* have to emit something at least once and complete.
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*
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* If any given observable errors at some point, `forkJoin` will error as well and immediately unsubscribe
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* from the other observables.
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*
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* Optionally `forkJoin` accepts a `resultSelector` function, that will be called with values which normally
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* would land in the emitted array. Whatever is returned by the `resultSelector`, will appear in the output
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* observable instead. This means that the default `resultSelector` can be thought of as a function that takes
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* all its arguments and puts them into an array. Note that the `resultSelector` will be called only
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* when `forkJoin` is supposed to emit a result.
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*
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* ## Examples
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*
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* Use `forkJoin` with a dictionary of observable inputs
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*
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* ```ts
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* import { forkJoin, of, timer } from 'rxjs';
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*
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* const observable = forkJoin({
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* foo: of(1, 2, 3, 4),
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* bar: Promise.resolve(8),
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* baz: timer(4000)
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* });
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* observable.subscribe({
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* next: value => console.log(value),
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* complete: () => console.log('This is how it ends!'),
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* });
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*
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* // Logs:
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* // { foo: 4, bar: 8, baz: 0 } after 4 seconds
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* // 'This is how it ends!' immediately after
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* ```
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*
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* Use `forkJoin` with an array of observable inputs
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*
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* ```ts
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* import { forkJoin, of, timer } from 'rxjs';
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*
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* const observable = forkJoin([
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* of(1, 2, 3, 4),
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* Promise.resolve(8),
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* timer(4000)
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* ]);
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* observable.subscribe({
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* next: value => console.log(value),
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* complete: () => console.log('This is how it ends!'),
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* });
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*
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* // Logs:
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* // [4, 8, 0] after 4 seconds
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* // 'This is how it ends!' immediately after
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* ```
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*
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* @see {@link combineLatest}
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* @see {@link zip}
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*
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* @param {...ObservableInput} args Any number of Observables provided either as an array or as an arguments
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* passed directly to the operator.
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* @param {function} [project] Function that takes values emitted by input Observables and returns value
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* that will appear in resulting Observable instead of default array.
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* @return {Observable} Observable emitting either an array of last values emitted by passed Observables
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* or value from project function.
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*/
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export function forkJoin(...args: any[]): Observable<any> {
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const resultSelector = popResultSelector(args);
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const { args: sources, keys } = argsArgArrayOrObject(args);
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const result = new Observable((subscriber) => {
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const { length } = sources;
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if (!length) {
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subscriber.complete();
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return;
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}
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const values = new Array(length);
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let remainingCompletions = length;
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let remainingEmissions = length;
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for (let sourceIndex = 0; sourceIndex < length; sourceIndex++) {
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let hasValue = false;
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innerFrom(sources[sourceIndex]).subscribe(
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createOperatorSubscriber(
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subscriber,
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(value) => {
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if (!hasValue) {
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hasValue = true;
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remainingEmissions--;
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}
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values[sourceIndex] = value;
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},
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() => remainingCompletions--,
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undefined,
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() => {
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if (!remainingCompletions || !hasValue) {
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if (!remainingEmissions) {
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subscriber.next(keys ? createObject(keys, values) : values);
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}
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subscriber.complete();
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}
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}
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)
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);
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}
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});
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return resultSelector ? result.pipe(mapOneOrManyArgs(resultSelector)) : result;
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}
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