Swift property wrappers initilaization error - ios

Question

I am trying to use PropertWrapper for email validation. But when i try to initialize the eamilId varaible with empty string i am getting error : Incorrect argument label in call (have 'wrappedValue:', expected 'emailId:')
Here is the code of My view controller
class ViewController: UIViewController {
var name: String = ""
#EmailWrapper var emailId: String = ""
override func viewDidLoad() {
super.viewDidLoad()
name = "User Name"
emailId = "user123#gmail.com"
updateUserDetails()
}
func updateUserDetails() {
if name.isEmpty || emailId.isEmpty {
print("Please enter valid Name and emailId")
}
else {
print("User data updated successfully")
}
}
}
And the code for my property wrapper is
#propertyWrapper
struct EmailWrapper {
private var value = ""
var wrappedValue: String {
set {
value = newValue
}
get {
return isValidEmail(value) ? value : ""
}
}
init(emailId: String) {
self.value = emailId
}
private func isValidEmail(_ email: String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"
let emailPred = NSPredicate(format:"SELF MATCHES %#", emailRegEx)
return emailPred.evaluate(with: email)
}
}
How can I initialize the emailId with default value (String()) in ViewController while using the EmailWrapper

Answer 1

When you apply a property wrapper:
#EmailWrapper var emailId: String = ""
the Swift compiler actually generates a call to the initialiser to the initialiser of the property wrapper like this:
EmailWrapper(wrappedValue: "")
However, EmailWrapper doesn't have such an initialiser. Its only initialiser has the argument label emailId: instead.
To fix this, you just need to change the argument label of the initialiser:
init(wrappedValue: String) {
self.value = wrappedValue
}