import type { DateArg } from "./types.js";
/**
 * @name formatRFC7231
 * @category Common Helpers
 * @summary Format the date according to the RFC 7231 standard (https://tools.ietf.org/html/rfc7231#section-7.1.1.1).
 *
 * @description
 * Return the formatted date string in RFC 7231 format.
 * The result will always be in UTC timezone.
 *
 * @param date - The original date
 *
 * @returns The formatted date string
 *
 * @throws `date` must not be Invalid Date
 *
 * @example
 * // Represent 18 September 2019 in RFC 7231 format:
 * const result = formatRFC7231(new Date(2019, 8, 18, 19, 0, 52))
 * //=> 'Wed, 18 Sep 2019 19:00:52 GMT'
 */
export declare function formatRFC7231(date: DateArg<Date> & {}): string;