import { Observable } from '../Observable';
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import { subscribeTo } from '../util/subscribeTo';
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import { ObservableInput, SchedulerLike, ObservedValueOf } from '../types';
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import { scheduled } from '../scheduled/scheduled';
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export function from<O extends ObservableInput<any>>(input: O): Observable<ObservedValueOf<O>>;
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/** @deprecated use {@link scheduled} instead. */
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export function from<O extends ObservableInput<any>>(input: O, scheduler: SchedulerLike): Observable<ObservedValueOf<O>>;
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/**
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* Creates an Observable from an Array, an array-like object, a Promise, an iterable object, or an Observable-like object.
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*
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* <span class="informal">Converts almost anything to an Observable.</span>
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*
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* 
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*
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* `from` converts various other objects and data types into Observables. It also converts a Promise, an array-like, or an
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* <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#iterable" target="_blank">iterable</a>
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* object into an Observable that emits the items in that promise, array, or iterable. A String, in this context, is treated
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* as an array of characters. Observable-like objects (contains a function named with the ES2015 Symbol for Observable) can also be
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* converted through this operator.
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*
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* ## Examples
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*
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* ### Converts an array to an Observable
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*
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* ```ts
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* import { from } from 'rxjs';
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*
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* const array = [10, 20, 30];
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* const result = from(array);
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*
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* result.subscribe(x => console.log(x));
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*
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* // Logs:
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* // 10
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* // 20
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* // 30
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* ```
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*
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* ---
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*
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* ### Convert an infinite iterable (from a generator) to an Observable
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*
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* ```ts
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* import { from } from 'rxjs';
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* import { take } from 'rxjs/operators';
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*
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* function* generateDoubles(seed) {
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* let i = seed;
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* while (true) {
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* yield i;
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* i = 2 * i; // double it
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* }
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* }
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*
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* const iterator = generateDoubles(3);
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* const result = from(iterator).pipe(take(10));
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*
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* result.subscribe(x => console.log(x));
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*
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* // Logs:
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* // 3
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* // 6
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* // 12
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* // 24
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* // 48
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* // 96
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* // 192
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* // 384
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* // 768
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* // 1536
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* ```
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*
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* ---
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*
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* ### With async scheduler
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*
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* ```ts
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* import { from, asyncScheduler } from 'rxjs';
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*
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* console.log('start');
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*
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* const array = [10, 20, 30];
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* const result = from(array, asyncScheduler);
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*
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* result.subscribe(x => console.log(x));
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*
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* console.log('end');
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*
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* // Logs:
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* // start
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* // end
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* // 10
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* // 20
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* // 30
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* ```
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*
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* @see {@link fromEvent}
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* @see {@link fromEventPattern}
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*
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* @param {ObservableInput<T>} A subscription object, a Promise, an Observable-like,
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* an Array, an iterable, or an array-like object to be converted.
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* @param {SchedulerLike} An optional {@link SchedulerLike} on which to schedule the emission of values.
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* @return {Observable<T>}
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* @name from
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* @owner Observable
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*/
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export function from<T>(input: ObservableInput<T>, scheduler?: SchedulerLike): Observable<T> {
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if (!scheduler) {
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if (input instanceof Observable) {
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return input;
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}
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return new Observable<T>(subscribeTo(input));
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} else {
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return scheduled(input, scheduler);
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}
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}
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