import { Observable } from '../Observable';
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import { ObservableInput, ObservedValuesFromArray, ObservedValueOf, SubscribableOrPromise } from '../types';
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import { isArray } from '../util/isArray';
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import { map } from '../operators/map';
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import { isObject } from '../util/isObject';
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import { isObservable } from '../util/isObservable';
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import { from } from './from';
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/* tslint:disable:max-line-length */
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// forkJoin(a$, b$, c$)
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T>(v1: SubscribableOrPromise<T>): Observable<[T]>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T, T2>(v1: ObservableInput<T>, v2: ObservableInput<T2>): Observable<[T, T2]>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T, T2, T3>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>): Observable<[T, T2, T3]>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T, T2, T3, T4>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>): Observable<[T, T2, T3, T4]>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T, T2, T3, T4, T5>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>): Observable<[T, T2, T3, T4, T5]>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T, T2, T3, T4, T5, T6>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, v6: ObservableInput<T6>): Observable<[T, T2, T3, T4, T5, T6]>;
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// forkJoin([a$, b$, c$]);
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// TODO(benlesh): Uncomment for TS 3.0
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// export function forkJoin(sources: []): Observable<never>;
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export function forkJoin<A>(sources: [ObservableInput<A>]): Observable<[A]>;
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export function forkJoin<A, B>(sources: [ObservableInput<A>, ObservableInput<B>]): Observable<[A, B]>;
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export function forkJoin<A, B, C>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>]): Observable<[A, B, C]>;
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export function forkJoin<A, B, C, D>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>]): Observable<[A, B, C, D]>;
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export function forkJoin<A, B, C, D, E>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>, ObservableInput<E>]): Observable<[A, B, C, D, E]>;
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export function forkJoin<A, B, C, D, E, F>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>, ObservableInput<E>, ObservableInput<F>]): Observable<[A, B, C, D, E, F]>;
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export function forkJoin<A extends ObservableInput<any>[]>(sources: A): Observable<ObservedValuesFromArray<A>[]>;
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// forkJoin({})
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export function forkJoin(sourcesObject: {}): Observable<never>;
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export function forkJoin<T, K extends keyof T>(sourcesObject: T): Observable<{ [K in keyof T]: ObservedValueOf<T[K]> }>;
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/** @deprecated resultSelector is deprecated, pipe to map instead */
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export function forkJoin(...args: Array<ObservableInput<any>|Function>): Observable<any>;
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/** @deprecated Use the version that takes an array of Observables instead */
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export function forkJoin<T>(...sources: ObservableInput<T>[]): Observable<T[]>;
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/* tslint:enable:max-line-length */
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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.</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, resulting stream will complete
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* immediately.
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*
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* `forkJoin` will wait for all passed observables to 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, resulting
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* array will have `n` values, where first value is the last thing emitted by the first observable,
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* second value is the last thing 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, resulting
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* objects will have the same keys as the dictionary passed, with their last values they've 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 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 resulting array to have the same length as the number of input observables, whenever any of
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* that 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 as well,
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* unless at any point some other observable completes without emitting value, which brings us back to
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* the previous case. Overall, in order for `forkJoin` to emit a value, all observables passed as arguments
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* have to emit something at least once and complete.
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*
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* If any input observable errors at some point, `forkJoin` will error as well and all other observables
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* will be immediately unsubscribed.
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*
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* Optionally `forkJoin` accepts project function, that will be called with values which normally
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* would land in emitted array. Whatever is returned by project function, will appear in output
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* observable instead. This means that default project can be thought of as a function that takes
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* all its arguments and puts them into an array. Note that project function will be called only
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* when output observable 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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* ```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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* ```ts
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* import { forkJoin, of } 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} sources 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(
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...sources: any[]
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): Observable<any> {
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if (sources.length === 1) {
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const first = sources[0];
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if (isArray(first)) {
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return forkJoinInternal(first, null);
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}
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// TODO(benlesh): isObservable check will not be necessary when deprecated path is removed.
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if (isObject(first) && Object.getPrototypeOf(first) === Object.prototype) {
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const keys = Object.keys(first);
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return forkJoinInternal(keys.map(key => first[key]), keys);
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}
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}
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// DEPRECATED PATHS BELOW HERE
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if (typeof sources[sources.length - 1] === 'function') {
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const resultSelector = sources.pop() as Function;
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sources = (sources.length === 1 && isArray(sources[0])) ? sources[0] : sources;
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return forkJoinInternal(sources, null).pipe(
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map((args: any[]) => resultSelector(...args))
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);
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}
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return forkJoinInternal(sources, null);
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}
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function forkJoinInternal(sources: ObservableInput<any>[], keys: string[] | null): Observable<any> {
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return new Observable(subscriber => {
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const len = sources.length;
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if (len === 0) {
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subscriber.complete();
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return;
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}
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const values = new Array(len);
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let completed = 0;
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let emitted = 0;
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for (let i = 0; i < len; i++) {
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const source = from(sources[i]);
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let hasValue = false;
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subscriber.add(source.subscribe({
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next: value => {
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if (!hasValue) {
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hasValue = true;
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emitted++;
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}
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values[i] = value;
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},
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error: err => subscriber.error(err),
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complete: () => {
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completed++;
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if (completed === len || !hasValue) {
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if (emitted === len) {
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subscriber.next(keys ?
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keys.reduce((result, key, i) => (result[key] = values[i], result), {}) :
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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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