ViewController.swift

extension ViewController: ASAuthorizationControllerDelegate { // 1
    //2
    func authorizationController(controller: ASAuthorizationController, didCompleteWithAuthorization authorization: ASAuthorization) {
        if let appleIDCredential = authorization.credential as?  ASAuthorizationAppleIDCredential {
            let userIdentifier = appleIDCredential.user
            let fullName = appleIDCredential.fullName
            let email = appleIDCredential.email
            print("User id is \(userIdentifier) \n Full Name is \(String(describing: fullName)) \n Email id is \(String(describing: email))") }
    }
    //3
    func authorizationController(controller: ASAuthorizationController, didCompleteWithError error: Error) {
        print(error)
    }
}