export declare class StringUtils {
    static isEmpty(str: string): boolean;
    static isNotEmpty(str: string): boolean;
    static isBlank(str: string): boolean;
    static isNotBlank(str: string): boolean;
    static isFloat(str: string): boolean;
    static isInteger(str: string): boolean;
    static isEmail(str: string): boolean;
    static isIpv4(str: string): boolean;
    static isPort(str: string): boolean;
    static isTelephone(str: string): boolean;
    static isMobile(str: string): boolean;
    static isDomain(str: string): boolean;
    static isPostcode(str: string): boolean;
    static isIDCard(str: string): boolean;
    static format(str: string, ...args: string[]): string;
}