blob: 118f68bb9f6ca09eb72ec8907611c0e1e77c5f0a [file] [log] [blame]
/**
* Minimal `EventEmitter` interface that is molded against the Node.js
* `EventEmitter` interface.
*/
declare class EventEmitter<
EventTypes extends EventEmitter.ValidEventTypes = string | symbol,
Context extends any = any
> {
static prefixed: string | boolean;
/**
* Return an array listing the events for which the emitter has registered
* listeners.
*/
eventNames(): Array<EventEmitter.EventNames<EventTypes>>;
/**
* Return the listeners registered for a given event.
*/
listeners<T extends EventEmitter.EventNames<EventTypes>>(
event: T
): Array<EventEmitter.EventListener<EventTypes, T>>;
/**
* Return the number of listeners listening to a given event.
*/
listenerCount(event: EventEmitter.EventNames<EventTypes>): number;
/**
* Calls each of the listeners registered for a given event.
*/
emit<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
...args: EventEmitter.EventArgs<EventTypes, T>
): boolean;
/**
* Add a listener for a given event.
*/
on<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
fn: EventEmitter.EventListener<EventTypes, T>,
context?: Context
): this;
addListener<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
fn: EventEmitter.EventListener<EventTypes, T>,
context?: Context
): this;
/**
* Add a one-time listener for a given event.
*/
once<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
fn: EventEmitter.EventListener<EventTypes, T>,
context?: Context
): this;
/**
* Remove the listeners of a given event.
*/
removeListener<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
fn?: EventEmitter.EventListener<EventTypes, T>,
context?: Context,
once?: boolean
): this;
off<T extends EventEmitter.EventNames<EventTypes>>(
event: T,
fn?: EventEmitter.EventListener<EventTypes, T>,
context?: Context,
once?: boolean
): this;
/**
* Remove all listeners, or those of the specified event.
*/
removeAllListeners(event?: EventEmitter.EventNames<EventTypes>): this;
}
declare namespace EventEmitter {
export interface ListenerFn<Args extends any[] = any[]> {
(...args: Args): void;
}
export interface EventEmitterStatic {
new <
EventTypes extends ValidEventTypes = string | symbol,
Context = any
>(): EventEmitter<EventTypes, Context>;
}
/**
* `object` should be in either of the following forms:
* ```
* interface EventTypes {
* 'event-with-parameters': any[]
* 'event-with-example-handler': (...args: any[]) => void
* }
* ```
*/
export type ValidEventTypes = string | symbol | object;
export type EventNames<T extends ValidEventTypes> = T extends string | symbol
? T
: keyof T;
export type ArgumentMap<T extends object> = {
[K in keyof T]: T[K] extends (...args: any[]) => void
? Parameters<T[K]>
: T[K] extends any[]
? T[K]
: any[];
};
export type EventListener<
T extends ValidEventTypes,
K extends EventNames<T>
> = T extends string | symbol
? (...args: any[]) => void
: (
...args: ArgumentMap<Exclude<T, string | symbol>>[Extract<K, keyof T>]
) => void;
export type EventArgs<
T extends ValidEventTypes,
K extends EventNames<T>
> = Parameters<EventListener<T, K>>;
export const EventEmitter: EventEmitterStatic;
}
export = EventEmitter;