export declare namespace FormatKind {
    function isDate(str: string): boolean;
    function isTime(str: string, strictTimeZone?: boolean): boolean;
    function isDateTime(value: string, strictTimeZone?: boolean): boolean;
    function isEmail(value: string): boolean;
    function isUuid(value: string): boolean;
    function isUrl(value: string): boolean;
    function isIPv6(value: string): boolean;
    function isIPv4(value: string): boolean;
}