import { MessageFunctionType, Result } from '../types';
export interface IsURLErrors {
    TARGET_ARGUMENT_NOT_A_STRING: MessageFunctionType;
}
export declare const IS_URL_ERRORS: IsURLErrors;
/**
 * IsURL Options.
 */
export interface IsURLOptions {
    protocols?: string[];
    require_tld?: boolean;
    require_protocol?: boolean;
    require_host?: boolean;
    require_port?: boolean;
    require_valid_protocol?: boolean;
    allow_underscores?: boolean;
    host_whitelist?: false | string[];
    host_blacklist?: false | string[];
    allow_trailing_dot?: boolean;
    allow_query_components?: boolean;
    allow_protocol_relative_urls?: boolean;
    allow_fragments?: boolean;
    validate_length?: boolean;
}
/**
 * Checks whether the `target` string is valid URL
 *
 * ### Example
 * ```
 * expect((isURL('foobar.com').value).toBeTruthy()
 * ```
 * @param url The target string
 * @param options The options
 */
export declare function isURL(url: string, options: any): Result<boolean | undefined>;