Formatting a UITextField for credit card input like (xxxx xxxx xxxx xxxx)

Question

I want to format a UITextField for entering a credit card number into such that it only allows digits to be entered and automatically inserts spaces so that the

Answer 1

Found a GIST in Github that does exactly what I need in Swift3 (https://gist.github.com/nunogoncalves/6a8b4b21f4f69e0fc050190df96a1e56)

Implemented by doing ->

if creditCardNumberTextView.text?.characters.first == "3" {
    let validator = Validator(cardType: .americanExpress, value:  self.creditCardNumberTextView.text!).test()

      if validator == true {

       } else {

       }
   }

Works wonderfully in the APP I'm working out which uses credit cards.