import { Core } from '../../client/core';
/**
 * Allows extending properties and methods of an Extendable
 */
export type Extension<T extends Record<string, unknown>> = (
/** The extendable object to which this extension will be applied */
extendable: Extendable, 
/** An object with internal properties and methods not publicly accessible */
core: Core) => T;
/**
 * An object that can be extended.
 *
 * To extend here means to add or replace the existing properties of this object,
 * as well as kicking off any related procedures. Like a structure on which you can
 * attach lego bricks.
 *
 * Ex: a { movie: "Up" } object can be extended by adding an audienceScore
 * property to it, and kicking off an api call that will constantly update this property from
 * an IMDb api.
 */
export declare class Extendable {
    private readonly core;
    constructor(core: Core);
    extend<T extends Record<string, unknown>>(extension: Extension<T>): T & typeof this;
}