/*!
 * SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */
/**
 * Check wether a given string is a valid URL.
 *
 * @param str - The potential URL
 */
export declare function isUrl(str: string): boolean;