Front end of the Slack clone application.

observeOn.js 3.1KB

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  1. "use strict";
  2. var observeOn_1 = require('../operators/observeOn');
  3. /**
  4. *
  5. * Re-emits all notifications from source Observable with specified scheduler.
  6. *
  7. * <span class="informal">Ensure a specific scheduler is used, from outside of an Observable.</span>
  8. *
  9. * `observeOn` is an operator that accepts a scheduler as a first parameter, which will be used to reschedule
  10. * notifications emitted by the source Observable. It might be useful, if you do not have control over
  11. * internal scheduler of a given Observable, but want to control when its values are emitted nevertheless.
  12. *
  13. * Returned Observable emits the same notifications (nexted values, complete and error events) as the source Observable,
  14. * but rescheduled with provided scheduler. Note that this doesn't mean that source Observables internal
  15. * scheduler will be replaced in any way. Original scheduler still will be used, but when the source Observable emits
  16. * notification, it will be immediately scheduled again - this time with scheduler passed to `observeOn`.
  17. * An anti-pattern would be calling `observeOn` on Observable that emits lots of values synchronously, to split
  18. * that emissions into asynchronous chunks. For this to happen, scheduler would have to be passed into the source
  19. * Observable directly (usually into the operator that creates it). `observeOn` simply delays notifications a
  20. * little bit more, to ensure that they are emitted at expected moments.
  21. *
  22. * As a matter of fact, `observeOn` accepts second parameter, which specifies in milliseconds with what delay notifications
  23. * will be emitted. The main difference between {@link delay} operator and `observeOn` is that `observeOn`
  24. * will delay all notifications - including error notifications - while `delay` will pass through error
  25. * from source Observable immediately when it is emitted. In general it is highly recommended to use `delay` operator
  26. * for any kind of delaying of values in the stream, while using `observeOn` to specify which scheduler should be used
  27. * for notification emissions in general.
  28. *
  29. * @example <caption>Ensure values in subscribe are called just before browser repaint.</caption>
  30. * const intervals = Rx.Observable.interval(10); // Intervals are scheduled
  31. * // with async scheduler by default...
  32. *
  33. * intervals
  34. * .observeOn(Rx.Scheduler.animationFrame) // ...but we will observe on animationFrame
  35. * .subscribe(val => { // scheduler to ensure smooth animation.
  36. * someDiv.style.height = val + 'px';
  37. * });
  38. *
  39. * @see {@link delay}
  40. *
  41. * @param {IScheduler} scheduler Scheduler that will be used to reschedule notifications from source Observable.
  42. * @param {number} [delay] Number of milliseconds that states with what delay every notification should be rescheduled.
  43. * @return {Observable<T>} Observable that emits the same notifications as the source Observable,
  44. * but with provided scheduler.
  45. *
  46. * @method observeOn
  47. * @owner Observable
  48. */
  49. function observeOn(scheduler, delay) {
  50. if (delay === void 0) { delay = 0; }
  51. return observeOn_1.observeOn(scheduler, delay)(this);
  52. }
  53. exports.observeOn = observeOn;
  54. //# sourceMappingURL=observeOn.js.map