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

elementAt.d.ts 1.9KB

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  1. import { MonoTypeOperatorFunction } from '../types';
  2. /**
  3. * Emits the single value at the specified `index` in a sequence of emissions
  4. * from the source Observable.
  5. *
  6. * <span class="informal">Emits only the i-th value, then completes.</span>
  7. *
  8. * ![](elementAt.png)
  9. *
  10. * `elementAt` returns an Observable that emits the item at the specified
  11. * `index` in the source Observable, or a default value if that `index` is out
  12. * of range and the `default` argument is provided. If the `default` argument is
  13. * not given and the `index` is out of range, the output Observable will emit an
  14. * `ArgumentOutOfRangeError` error.
  15. *
  16. * ## Example
  17. * Emit only the third click event
  18. * ```ts
  19. * import { fromEvent } from 'rxjs';
  20. * import { elementAt } from 'rxjs/operators';
  21. *
  22. * const clicks = fromEvent(document, 'click');
  23. * const result = clicks.pipe(elementAt(2));
  24. * result.subscribe(x => console.log(x));
  25. *
  26. * // Results in:
  27. * // click 1 = nothing
  28. * // click 2 = nothing
  29. * // click 3 = MouseEvent object logged to console
  30. * ```
  31. *
  32. * @see {@link first}
  33. * @see {@link last}
  34. * @see {@link skip}
  35. * @see {@link single}
  36. * @see {@link take}
  37. *
  38. * @throws {ArgumentOutOfRangeError} When using `elementAt(i)`, it delivers an
  39. * ArgumentOutOrRangeError to the Observer's `error` callback if `i < 0` or the
  40. * Observable has completed before emitting the i-th `next` notification.
  41. *
  42. * @param {number} index Is the number `i` for the i-th source emission that has
  43. * happened since the subscription, starting from the number `0`.
  44. * @param {T} [defaultValue] The default value returned for missing indices.
  45. * @return {Observable} An Observable that emits a single item, if it is found.
  46. * Otherwise, will emit the default value if given. If not, then emits an error.
  47. * @method elementAt
  48. * @owner Observable
  49. */
  50. export declare function elementAt<T>(index: number, defaultValue?: T): MonoTypeOperatorFunction<T>;