Extended a String class for make function validation

validation.swift

extension String {
    func isEmail() -> Bool {
        let regex = try! NSRegularExpression(pattern: "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}$", options: [.CaseInsensitive])
        
        return regex.firstMatchInString(self, options:[], range: NSMakeRange(0, utf16.count)) != nil
    }
    
    func isDni() -> Bool {
        let regex = try! NSRegularExpression(pattern: "^[0-9]{8}$", options: [.CaseInsensitive])
        
        return regex.firstMatchInString(self, options:[], range: NSMakeRange(0, utf16.count)) != nil
    }
    
    func isPassword() -> Bool {
        let regex = try! NSRegularExpression(pattern: "^[0-9]{6}$", options: [.CaseInsensitive])
        
        return regex.firstMatchInString(self, options: [], range: NSMakeRange(0, utf16.count)) != nil
    }
    
    
}