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- import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
- import { operate } from '../util/lift';
- /**
- * 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.
- *
- * 
- *
- * ## Example
- *
- * Given the following code:
- *
- * ```ts
- * import { of, merge } from 'rxjs';
- *
- * const a = of(1, 2, 3);
- * const b = of(4, 5, 6);
- *
- * merge(a, b).subscribe(console.log);
- *
- * // Outputs
- * // 1
- * // 2
- * // 3
- * // 4
- * // 5
- * // 6
- * ```
- *
- * Both Observable `a` and `b` will emit their values directly and synchronously once they are subscribed to.
- *
- * If we instead use the `subscribeOn` operator declaring that we want to use the {@link asyncScheduler} for values emitted by Observable `a`:
- *
- * ```ts
- * import { of, subscribeOn, asyncScheduler, merge } from 'rxjs';
- *
- * const a = of(1, 2, 3).pipe(subscribeOn(asyncScheduler));
- * const b = of(4, 5, 6);
- *
- * merge(a, b).subscribe(console.log);
- *
- * // Outputs
- * // 4
- * // 5
- * // 6
- * // 1
- * // 2
- * // 3
- * ```
- *
- * 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 scheduler The {@link SchedulerLike} to perform subscription actions on.
- * @param delay A delay to pass to the scheduler to delay subscriptions
- * @return A function that returns an Observable modified so that its
- * subscriptions happen on the specified {@link SchedulerLike}.
- */
- export function subscribeOn<T>(scheduler: SchedulerLike, delay: number = 0): MonoTypeOperatorFunction<T> {
- return operate((source, subscriber) => {
- subscriber.add(scheduler.schedule(() => source.subscribe(subscriber), delay));
- });
- }
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