export type UrlString = `http://${string}` | `https://${string}` | `/${string}`;
/**
 * A type guard for determining if a value is a valid URL.
 * @param value - The value to check.
 * @returns `true` if the value is a valid URL, otherwise `false`.
 * @group Type Guards
 */
export declare function isUrlString(value: unknown): value is UrlString;
/**
 * Converts a string to a valid URL.
 * @param value - The string to convert.
 * @returns The valid URL.
 */
export declare function asUrlString(value: string): UrlString;