/**
 * Checks if argument is a ISO 8601 Date String.
 *
 * Such a string is 24 ((YYYY-MM-DDTHH:mm:ss.sssZ)
 * or
 * 27 (±YYYYYY-MM-DDTHH:mm:ss.sssZ)
 *
 * characters long.
 *
 * @param value The value being checked.
 * @return True if the value is an instance of an ISOString date.
 */
export declare function isISODateString(value: any): boolean;