/*************************************************************************
 * Copyright 2020 Adobe
 * All Rights Reserved.
 *
 * NOTICE: Adobe permits you to use, modify, and distribute this file in
 * accordance with the terms of the Adobe license agreement accompanying
 * it. If you have received this file from a source other than Adobe,
 * then your use, modification, or distribution of it requires the prior
 * written permission of Adobe.
 **************************************************************************/
/**
 * @packageDocumentation
 * @module "index"
 */
/**
 * @ignore
 */
export default interface EventEmitter<T = Record<string, any>> {
    /**
     * Register an event handler for the given type.
     * @param type Type of event to listen for.
     * @param handler Function to call in response to given event.
     * @category EventEmitter
     */
    on<K extends keyof T>(type: K, handler: (event?: T[K]) => void): void;
    /**
     * Remove an event handler for the given type.
     * @param type Type of event to unregister `handler` from.
     * @param handler Handler function to remove.
     * @category EventEmitter
     */
    off<K extends keyof T>(type: K, handler: (event?: T[K]) => void): void;
    /**
     * Invoke all handlers for the given type.
     * @param type The event type to invoke.
     * @param event Any value (object is recommended and powerful), passed to each handler.
     * @category EventEmitter
     */
    emit<K extends keyof T>(type: K, event?: T[K]): void;
}