export type Arguments<T> = [T] extends [(...args: infer U) => any] ? U : [T] extends [void] ? [] : [T];
export type EventsT = Record<string, (...args: any) => void>;
type Callback = (...args: any[]) => void;
type EventData = {
    callback: Callback;
    ctx?: any;
};
export declare class Emitter<T extends EventsT = any> {
    e: Map<keyof T, EventData[]>;
    constructor();
    on<E extends keyof T>(event: E, callback: T[E], ctx?: any): this;
    private _on;
    once<E extends keyof T>(event: E, callback: T[E], ctx?: any): void;
    emit<E extends keyof T>(event: E | string, ...args: Arguments<T[E]> | any[]): this | undefined;
    off<E extends keyof T>(event: E, callback?: T[E]): this | undefined;
}
export {};