1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950 |
- import { Observable } from '../Observable';
- import { IScheduler } from '../Scheduler';
- /**
- *
- * Re-emits all notifications from source Observable with specified scheduler.
- *
- * <span class="informal">Ensure a specific scheduler is used, from outside of an Observable.</span>
- *
- * `observeOn` is an operator that accepts a scheduler as a first parameter, which will be used to reschedule
- * notifications emitted by the source Observable. It might be useful, if you do not have control over
- * internal scheduler of a given Observable, but want to control when its values are emitted nevertheless.
- *
- * Returned Observable emits the same notifications (nexted values, complete and error events) as the source Observable,
- * but rescheduled with provided scheduler. Note that this doesn't mean that source Observables internal
- * scheduler will be replaced in any way. Original scheduler still will be used, but when the source Observable emits
- * notification, it will be immediately scheduled again - this time with scheduler passed to `observeOn`.
- * An anti-pattern would be calling `observeOn` on Observable that emits lots of values synchronously, to split
- * that emissions into asynchronous chunks. For this to happen, scheduler would have to be passed into the source
- * Observable directly (usually into the operator that creates it). `observeOn` simply delays notifications a
- * little bit more, to ensure that they are emitted at expected moments.
- *
- * As a matter of fact, `observeOn` accepts second parameter, which specifies in milliseconds with what delay notifications
- * will be emitted. The main difference between {@link delay} operator and `observeOn` is that `observeOn`
- * will delay all notifications - including error notifications - while `delay` will pass through error
- * from source Observable immediately when it is emitted. In general it is highly recommended to use `delay` operator
- * for any kind of delaying of values in the stream, while using `observeOn` to specify which scheduler should be used
- * for notification emissions in general.
- *
- * @example <caption>Ensure values in subscribe are called just before browser repaint.</caption>
- * const intervals = Rx.Observable.interval(10); // Intervals are scheduled
- * // with async scheduler by default...
- *
- * intervals
- * .observeOn(Rx.Scheduler.animationFrame) // ...but we will observe on animationFrame
- * .subscribe(val => { // scheduler to ensure smooth animation.
- * someDiv.style.height = val + 'px';
- * });
- *
- * @see {@link delay}
- *
- * @param {IScheduler} scheduler Scheduler that will be used to reschedule notifications from source Observable.
- * @param {number} [delay] Number of milliseconds that states with what delay every notification should be rescheduled.
- * @return {Observable<T>} Observable that emits the same notifications as the source Observable,
- * but with provided scheduler.
- *
- * @method observeOn
- * @owner Observable
- */
- export declare function observeOn<T>(this: Observable<T>, scheduler: IScheduler, delay?: number): Observable<T>;
|