User validation: Add validation case

[Gafiliano Gapili]

Description:

username should not contain spaces " ". It is possible to use dash or underscore to separate between words like john-doe or john_doe.

Task

• Add validation case in

  Teddit/Teddit/RegisterViewController.swift

  Lines 56 to 88 in 50e9545

   func validateUsername() throws -> String { 
       let username = usernameField.text! 
       if username.isEmpty { 
           throw ValidationError("Username cannot be empty.") 
       } 
        
       if username.count < 3 || username.count > 20 { 
           throw ValidationError("Username must be 4-20 characters.") 
       } 
    
       for char in username { 
           if char == "_" { 
               continue 
           } 
            
           if !char.isLetter && !char.isNumber { 
               throw ValidationError("Username must not contain special characters.") 
           } 
       } 
        
       var entity: User? = nil 
       do { 
           entity = try userRepo!.findByUsername(username: username) 
       } catch { 
           print("Cannot fetch from Core Data: \(error)") 
       } 
        
       if entity != nil { 
           throw ValidationError("Username is already taken.") 
       } 
        
       return username 
   } 

[Gafiliano Gapili]

fixed