Swift Initializer for conditional binding must have Optional type, not 'Bool' error with if let statement

Question

So i am coding an app in Xcode and this is a part of the code:

func Signup(_ sender: Any) {
        if let email = Email.text != nil, let password =

In the 2nd line i get a error

Initializer for conditional binding must have Optional type, not 'Bool'

Can you help me please?

BTW - It is standard practice that variable and function names start with lowercase letters. Class and struct names start with uppercase letters. — rmaddy, Feb 24 '19 at 15:53
Btw The textfield never returns nil. The comparison against nil will always fail. Even if you assign nil to the text property and get its value right after it returns an empty string which is its default value. Considering this you can just force unwrap it `let emailText = email.text!` — Leo Dabus, Feb 24 '19 at 17:17
If you are coding for iOS 10 or later and need to know if the text field is empty or not you can use UIKeyInput protocol method hasText https://developer.apple.com/documentation/uikit/uikeyinput/1614457-hastext in your case `if email.hasText {` — Leo Dabus, Feb 24 '19 at 17:24

Rob · Answer 1 · 2019-02-26T23:18:32.497

Obviously, you should eliminate that != nil.

I’d also recommend:

trimming whitespace so someone doesn’t enter space to get past the validation;
use isEmpty of the trimmed string to make sure there’s something there;
start properties and method names with lowercase letters;
I personally give my UITextField properties a TextField suffix (so I can distinguish the emailTextField text field from the email string.

Thus, perhaps something like:

@IBAction func didTapSignup(_ sender: Any) {
    guard let email = emailTextField.text?.trimmingCharacters(in: .whitespaces),
        !email.isEmpty,
        let password = passwordTextField.text?.trimmingCharacters(in: .whitespaces),
        !password.isEmpty else {
            // tell the user that validation failed here ...

            // ... and then return
            return
    }

    // do something with `email` and `password`
}

You might want to check, for example, that the email and password pass some rudimentary rules:

let emailRegexString = "^[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$"  // oversimplified email regex

func isAcceptable(email: String, password: String) -> Bool {
    let isEmailAcceptable = email.range(of: emailRegexString, options: .regularExpression) != nil
    let isPasswordAcceptable = password.count > 4

    return isEmailAcceptable && isPasswordAcceptable
}

And then

@IBAction func didTapSignup(_ sender: Any) {
    guard let email = emailTextField.text?.trimmingCharacters(in: .whitespaces),
        let password = passwordTextField.text?.trimmingCharacters(in: .whitespaces),
        isAcceptable(email: email, password: password) else {
            // tell the user that validation failed here ...

            // ... and then return
            return
    }

    // do something with `email` and `password`
}

Note, that regex is a grossly over-simplified email validation. But you can go nuts on the regex if you really want.

I’d also, at a bare minimum, set up my email and password text fields so that spaces are not allowed. So, specify the delegate for the email and password text fields and then prohibit spaces:

extension ViewController: UITextFieldDelegate {

    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        return string.rangeOfCharacter(from: .whitespacesAndNewlines) == nil
    }

}

Swift Initializer for conditional binding must have Optional type, not 'Bool' error with if let statement

1 Answers1