Just like crypto, you really shouldn't roll your own phone number validation libraries. Just use Google's libphonenumber[0]. There's an iOS port of it [1]. [0]

Just like crypto, you really shouldn't roll your own phone number validation libraries. Just use Google's libphonenumber[0]. There's an iOS port of it [1]. [0] https://github.com/googlei18n/libphonenumber https://github.com/googlei18n/libphonenumber [1] https://github.com/iziz/libPhoneNumber-iOS https://github.com/iziz/libPhoneNumber-iOS