/**
 * Converts given string to an URL which starts with `https://` and ends with
 * a single trailing slash.
 *
 * @example
 * // Returns "https://www.bynder.com/"
 * ensureValidUrl("www.bynder.com")
 *
 * @example
 * // Replaces http with https to return "https://www.bynder.com/"
 * ensureValidUrl("http://www.bynder.com/")
 */
export declare function ensureValidUrl(url: string): string;