Repositorio del curso CCOM4030 el semestre B91 del proyecto Artesanías con el Instituto de Cultura

observeOn.d.ts 4.3KB

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  1. import { Operator } from '../Operator';
  2. import { Subscriber } from '../Subscriber';
  3. import { Notification } from '../Notification';
  4. import { MonoTypeOperatorFunction, PartialObserver, SchedulerAction, SchedulerLike, TeardownLogic } from '../types';
  5. /**
  6. *
  7. * Re-emits all notifications from source Observable with specified scheduler.
  8. *
  9. * <span class="informal">Ensure a specific scheduler is used, from outside of an Observable.</span>
  10. *
  11. * `observeOn` is an operator that accepts a scheduler as a first parameter, which will be used to reschedule
  12. * notifications emitted by the source Observable. It might be useful, if you do not have control over
  13. * internal scheduler of a given Observable, but want to control when its values are emitted nevertheless.
  14. *
  15. * Returned Observable emits the same notifications (nexted values, complete and error events) as the source Observable,
  16. * but rescheduled with provided scheduler. Note that this doesn't mean that source Observables internal
  17. * scheduler will be replaced in any way. Original scheduler still will be used, but when the source Observable emits
  18. * notification, it will be immediately scheduled again - this time with scheduler passed to `observeOn`.
  19. * An anti-pattern would be calling `observeOn` on Observable that emits lots of values synchronously, to split
  20. * that emissions into asynchronous chunks. For this to happen, scheduler would have to be passed into the source
  21. * Observable directly (usually into the operator that creates it). `observeOn` simply delays notifications a
  22. * little bit more, to ensure that they are emitted at expected moments.
  23. *
  24. * As a matter of fact, `observeOn` accepts second parameter, which specifies in milliseconds with what delay notifications
  25. * will be emitted. The main difference between {@link delay} operator and `observeOn` is that `observeOn`
  26. * will delay all notifications - including error notifications - while `delay` will pass through error
  27. * from source Observable immediately when it is emitted. In general it is highly recommended to use `delay` operator
  28. * for any kind of delaying of values in the stream, while using `observeOn` to specify which scheduler should be used
  29. * for notification emissions in general.
  30. *
  31. * ## Example
  32. * Ensure values in subscribe are called just before browser repaint.
  33. * ```ts
  34. * import { interval } from 'rxjs';
  35. * import { observeOn } from 'rxjs/operators';
  36. *
  37. * const intervals = interval(10); // Intervals are scheduled
  38. * // with async scheduler by default...
  39. * intervals.pipe(
  40. * observeOn(animationFrameScheduler), // ...but we will observe on animationFrame
  41. * ) // scheduler to ensure smooth animation.
  42. * .subscribe(val => {
  43. * someDiv.style.height = val + 'px';
  44. * });
  45. * ```
  46. *
  47. * @see {@link delay}
  48. *
  49. * @param {SchedulerLike} scheduler Scheduler that will be used to reschedule notifications from source Observable.
  50. * @param {number} [delay] Number of milliseconds that states with what delay every notification should be rescheduled.
  51. * @return {Observable<T>} Observable that emits the same notifications as the source Observable,
  52. * but with provided scheduler.
  53. *
  54. * @method observeOn
  55. * @owner Observable
  56. */
  57. export declare function observeOn<T>(scheduler: SchedulerLike, delay?: number): MonoTypeOperatorFunction<T>;
  58. export declare class ObserveOnOperator<T> implements Operator<T, T> {
  59. private scheduler;
  60. private delay;
  61. constructor(scheduler: SchedulerLike, delay?: number);
  62. call(subscriber: Subscriber<T>, source: any): TeardownLogic;
  63. }
  64. /**
  65. * We need this JSDoc comment for affecting ESDoc.
  66. * @ignore
  67. * @extends {Ignored}
  68. */
  69. export declare class ObserveOnSubscriber<T> extends Subscriber<T> {
  70. private scheduler;
  71. private delay;
  72. /** @nocollapse */
  73. static dispatch(this: SchedulerAction<ObserveOnMessage>, arg: ObserveOnMessage): void;
  74. constructor(destination: Subscriber<T>, scheduler: SchedulerLike, delay?: number);
  75. private scheduleMessage;
  76. protected _next(value: T): void;
  77. protected _error(err: any): void;
  78. protected _complete(): void;
  79. }
  80. export declare class ObserveOnMessage {
  81. notification: Notification<any>;
  82. destination: PartialObserver<any>;
  83. constructor(notification: Notification<any>, destination: PartialObserver<any>);
  84. }