blob: b67954e6f021486e43ee1d004c87f33bd260b87a [file] [log] [blame]
import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
/**
* Asynchronously subscribes Observers to this Observable on the specified {@link SchedulerLike}.
*
* With `subscribeOn` you can decide what type of scheduler a specific Observable will be using when it is subscribed to.
*
* Schedulers control the speed and order of emissions to observers from an Observable stream.
*
* ![](subscribeOn.png)
*
* ## Example
* Given the following code:
* ```javascript
* import { of, merge } from 'rxjs';
*
* const a = of(1, 2, 3, 4);
* const b = of(5, 6, 7, 8, 9);
* merge(a, b).subscribe(console.log);
* ```
*
* Both Observable `a` and `b` will emit their values directly and synchronously once they are subscribed to.
* This will result in the output of `1 2 3 4 5 6 7 8 9`.
*
* But if we instead us the `subscribeOn` operator declaring that we want to use the {@link asyncScheduler} for values emited by Observable `a`:
* ```javascript
* import { of, merge, asyncScheduler } from 'rxjs';
* import { subscribeOn } from 'rxjs/operators';
*
* const a = of(1, 2, 3, 4).pipe(subscribeOn(asyncScheduler));
* const b = of(5, 6, 7, 8, 9);
* merge(a, b).subscribe(console.log);
* ```
*
* The output will instead be `5 6 7 8 9 1 2 3 4`.
* The reason for this is that Observable `b` emits its values directly and synchronously like before
* but the emissions from `a` are scheduled on the event loop because we are now using the {@link asyncScheduler} for that specific Observable.
*
* @param {SchedulerLike} scheduler - The {@link SchedulerLike} to perform subscription actions on.
* @return {Observable<T>} The source Observable modified so that its subscriptions happen on the specified {@link SchedulerLike}.
.
* @method subscribeOn
* @owner Observable
*/
export declare function subscribeOn<T>(scheduler: SchedulerLike, delay?: number): MonoTypeOperatorFunction<T>;