export declare type EventType = string | symbol; export declare type Handler<T = unknown> = (event: T) => void; export declare type WildcardHandler<T = Record<string, unknown>> = (type: keyof T, event: T[keyof T]) => void; export declare type EventHandlerList<T = unknown> = Array<Handler<T>>; export declare type WildCardEventHandlerList<T = Record<string, unknown>> = Array<WildcardHandler<T>>; export declare type EventHandlerMap<Events extends Record<EventType, unknown>> = Map<keyof Events | '*', EventHandlerList<Events[keyof Events]> | WildCardEventHandlerList<Events>>; export interface Emitter<Events extends Record<EventType, unknown>> { all: EventHandlerMap<Events>; on<Key extends keyof Events>(type: Key, handler: Handler<Events[Key]>): void; on(type: '*', handler: WildcardHandler<Events>): void; off<Key extends keyof Events>(type: Key, handler?: Handler<Events[Key]>): void; off(type: '*', handler: WildcardHandler<Events>): void; emit<Key extends keyof Events>(type: Key, event: Events[Key]): void; emit<Key extends keyof Events>(type: undefined extends Events[Key] ? Key : never): void; } /** * Mitt: Tiny (~200b) functional event emitter / pubsub. * @name mitt * @returns {Mitt} */ export default function mitt<Events extends Record<EventType, unknown>>(all?: EventHandlerMap<Events>): Emitter<Events>;