EventEmitter.d.ts 2.6 KB

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  1. type EventListener<Events, EventType extends keyof Events> = Events[EventType];
  2. export type EventParameters<Events, EventType extends keyof Events> = {
  3. [Event in EventType]: EventListener<Events, EventType> extends (...args: infer P) => any ? P : never;
  4. }[EventType];
  5. export declare class EventEmitter<EventTypes extends Record<string, (...args: any) => any>> {
  6. #private;
  7. /**
  8. * Adds the listener function to the end of the listeners array for the event.
  9. * No checks are made to see if the listener has already been added. Multiple calls passing
  10. * the same combination of event and listener will result in the listener being added, and
  11. * called, multiple times.
  12. * @returns this, so that calls can be chained
  13. */
  14. on<Event extends keyof EventTypes>(event: Event, listener: EventListener<EventTypes, Event>): this;
  15. /**
  16. * Removes the specified listener from the listener array for the event.
  17. * off() will remove, at most, one instance of a listener from the listener array. If any single
  18. * listener has been added multiple times to the listener array for the specified event, then
  19. * off() must be called multiple times to remove each instance.
  20. * @returns this, so that calls can be chained
  21. */
  22. off<Event extends keyof EventTypes>(event: Event, listener: EventListener<EventTypes, Event>): this;
  23. /**
  24. * Adds a one-time listener function for the event. The next time the event is triggered,
  25. * this listener is removed and then invoked.
  26. * @returns this, so that calls can be chained
  27. */
  28. once<Event extends keyof EventTypes>(event: Event, listener: EventListener<EventTypes, Event>): this;
  29. /**
  30. * This is similar to `.once()`, but returns a Promise that resolves the next time
  31. * the event is triggered, instead of calling a listener callback.
  32. * @returns a Promise that resolves the next time given event is triggered,
  33. * or rejects if an error is emitted. (If you request the 'error' event,
  34. * returns a promise that resolves with the error).
  35. *
  36. * Example:
  37. *
  38. * const message = await stream.emitted('message') // rejects if the stream errors
  39. */
  40. emitted<Event extends keyof EventTypes>(event: Event): Promise<EventParameters<EventTypes, Event> extends [infer Param] ? Param : EventParameters<EventTypes, Event> extends [] ? void : EventParameters<EventTypes, Event>>;
  41. protected _emit<Event extends keyof EventTypes>(this: EventEmitter<EventTypes>, event: Event, ...args: EventParameters<EventTypes, Event>): void;
  42. protected _hasListener(event: keyof EventTypes): boolean;
  43. }
  44. export {};
  45. //# sourceMappingURL=EventEmitter.d.ts.map