Refactoring - pull up method

This refactoring is applied when two classes have an identical method. It can be moved up to the parent.

Let's continue the example from previous post:

class BankAccount {
    var balance : Float = 0
}

class CheckingAccount: BankAccount {
    func displayAlert(){
        if balance < 0 {
            print("You have a negative balance of \(balance).")
        }
    }
}

class SavingAccount: BankAccount {
    func displayAlert(){
        if balance < 0 {
            print("You have a negative balance of \(balance).")
        }
    }
}

We have just refactored the balance field, but we noticed we also have a method (displayAlert) that is identical. We can apply the same refactoring and move it up the hierarchy.

class BankAccount {

    var balance: Float = 0

    

    func displayAlert(){

        if balance < 0 {

            print("You have a negative balance of \(balance).")

        }

    }

}

class CheckingAccount: BankAccount {

}

class SavingAccount: BankAccount {

}