Login authentication problem with firebase in Xcode - ios

Question

I try to do firebase authenticate. I've installed all necessary pods and made all needed methods. When I click "Login" even when I entered bad email and password, I get error message (e.g. bad password) and immediately my view is changed to my target view (next ViewController). I don't know why it is happening, because I made if statement. I want to have my login page unless I enter correct email and password.
#IBAction func loginTapped(_ sender: UIButton) {
if let email = emailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines), let password =
passwordTextField.text?.trimmingCharacters(in:
.whitespacesAndNewlines) {
Auth.auth().signIn(withEmail: email, password: password) { (authResult, error) in
if let e = error {
// Can't sign in
self.errorLabel.text = error!.localizedDescription
self.errorLabel.alpha = 1
} else {
self.performSegue(withIdentifier: "loginToHome", sender: self)
}
}
}
}

Answer 1

You may try to check if an error exists first. If yes, the error message will be shown. If there's no error, the login success segue will be performed.
#IBAction func loginTapped(_ sender: UIButton) {
if let email = emailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines), let password = passwordTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) {
Auth.auth().signIn(withEmail: email, password: password) { (authResult, error) in
if error != nil { // there's an error - show error label
self.errorLabel.text = error!.localizedDescription
self.errorLabel.alpha = 1
} else { //no error - perform segue
// no error - perform segue
self.performSegue(withIdentifier: "loginToHome", sender: self) } } } }
Edit: You may also add return after checking that an error exists - the codes that follow after it will not be performed:
#IBAction func loginTapped(_ sender: UIButton) {
if let email = emailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines), let password = passwordTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) {
Auth.auth().signIn(withEmail: email, password: password) { (authResult, error) in
if error != nil { // there's an error - show error label
self.errorLabel.text = error!.localizedDescription
self.errorLabel.alpha = 1
return // activities that follow will not be performed
} else { //no error - perform segue
self.performSegue(withIdentifier: "loginToHome", sender: self) } } } }