export interface IEventCollection {
    [key: string]: IEventListener[];
}
export declare type IEventListener = () => void;
export declare class EventEmitter {
    events: IEventCollection;
    constructor();
    on(event: string, listener: IEventListener): void;
    off(event: string, listener: IEventListener): void;
    emit(event: string, ...args: any[]): void;
    once(event: string, listener: IEventListener): void;
}