import { type EmailAddress } from './email';
/**
 * Domain name portion of an email address (e.g., "example.com").
 */
export type EmailAddressDomain = string;
/**
 * Extracts unique domain names from a list of email addresses (case-insensitive).
 *
 * @param addresses - Array of email addresses to extract domains from
 * @returns Array of unique lowercase domain strings
 */
export declare function readDomainsFromEmailAddresses(addresses: EmailAddress[]): EmailAddressDomain[];
/**
 * Extracts the domain portion from a single email address.
 *
 * @param address - The email address to extract the domain from
 * @returns The lowercase domain string
 */
export declare function readDomainFromEmailAddress(address: EmailAddress): EmailAddressDomain;
/**
 * Reads a domain from various input formats including URLs, email addresses, and raw domains.
 *
 * Supported formats:
 * - A url: www.test.com
 * - A url with the protocol (://): https://www.test.com
 * - An email address: test@test.com
 * - A domain: test.com
 *
 * The "www." prefix is stripped from URL-style inputs since emails typically don't use it.
 *
 * @param urlLikeInput - A URL, email address, or domain string
 * @returns The extracted domain
 */
export declare function readEmailDomainFromUrlOrEmailAddress(urlLikeInput: string | EmailAddress | EmailAddressDomain): EmailAddressDomain;