export declare function isExternal(path: string): boolean;
export declare function validUsername(str: string): boolean;
export declare function validURL(url: string): boolean;
export declare function validLowerCase(str: string): boolean;
export declare function validUpperCase(str: string): boolean;
export declare function validAlphabets(str: string): boolean;
export declare function isString(str: any): boolean;
export declare function isArray(arg: string): boolean;