/**
 * Formats a given domain to `example.com` format.
 * - Strips protocol and leading www
 * - Removes trailing slash
 * - Lowercases the domain
 */
export declare function formatDomain(domain: string): string;
/**
 * Extracts the subdomain from a given domain.
 * Returns null if no subdomain is present.
 */
export declare function extractSubdomain(domain: string): string | null;
/**
 * Gets the root domain (e.g., example.com) from a domain that may include a subdomain.
 */
export declare function getRootDomain(domain: string): string;
/**
 * Checks if the given domain is valid.
 */
export declare function checkDomain(domain: string): boolean;
/**
 * Converts a date string to a timestamp.
 */
export declare function dateToTimestamp(dateString: string): number;