/*!
 * Copyright (c) Microsoft. All rights reserved.
 * Licensed under the MIT license. See LICENSE file in the project.
 */
type Handler = (...args: any[]) => any;
interface DestroyObject {
    destroy: (key: string, handler?: Handler) => void;
}
/**
 * A mixin that adds support for event emitting
 */
export declare class EventEmitter {
    private listeners;
    /**
     * Adds an event listener for the given event
     */
    on(key: string, handler?: Handler): DestroyObject | undefined;
    /**
     * Removes an event listener for the given event
     */
    off(key: string, handler?: Handler): void;
    /**
     * Raises the given event
     */
    emit(name: string, ...args: any[]): void;
    /**
     * Returns the namespace and event name
     * @param eventKey - The event key, either "<event>" or "<event>.<namespace>"
     */
    private getNamespaceAndEvent;
}
export declare const eventEmitter: () => EventEmitter;
export {};