package model import ( "fmt" ) type User struct { ID int Name string Mail string Username string Password string } func (u *User) IsValid() error { if u.Name == "" { return fmt.Errorf("name must not be empty") } if u.Mail == "" { return fmt.Errorf("mail must not be empty") } if u.Username == "" { return fmt.Errorf("username must not be empty") } if u.Password == "" { return fmt.Errorf("password must not be empty") } return nil }