Demonstrating a traditional way to validate user input.

TraditonalVerification.kt

fun validateUserInput(): Boolean {

   val emailPattern = Pattern.compile("my-perfect-regex")
   val passwordPattern = Pattern.compile("my-perfect-regex")
  
    if(email == null || email.length > 30 || !emailPattern.matcher(email).matches()) {
        // Handle Email is invalid
    } else if (password == null || password.length > 30 || !passwordPattern.matcher(password).matches()) {
       // Handle Password is invalid
    } else {
        return true
    }
  
    return false
}

OR

fun validateUserInput(): Boolean {

   val emailPattern = Pattern.compile("my-perfect-regex")
   val passwordPattern = Pattern.compile("my-perfect-regex")
  
    if(email == null) {
        // Handle Email is empty
    } else if(email.length > 30) {
        // Handle Email length too long
    } else if(!emailPattern.matcher(email).matches()) {
        // Handle Email is invalid
    } else if (password == null) {
       // Handle Password is empty
    } else if(!passwordPattern.matcher(password).matches()) {
        // Handle Password is invalid
    } else if (password.length > 30) {
       // Handle Password length too long
    } else {
        return true
    }
  
    return false
}