/**
 * @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
/**
 * Ensures that passed function will be executed only once.
 */
export declare function once<A extends Array<any>, R = void>(fn: (...args: A) => R): (...args: A) => R;