Can't use private property in extensions in another file

Question

I can\'t use private property in extension. My extension is in another file.

How can I use private property in extension?

Answer 1

While @nhgrif is correct about how painful is that protected is missing in Swift, There is a way around.

Wrap your object with protocol, and declare only about the methods and properties that you wish to expose.

For Example

MyUtiltyClass.swift

protocol IMyUtiltyClass {
    func doSomething()
}

class MyUtiltyClass : IMyUtiltyClass {

    static let shared : IMyUtiltyClass = MyUtiltyClass()

    /*private*/
    func doSomethingPrivately() {

    }
}

MyUtiltyClass+DoSomething.swift

extension MyUtiltyClass {
    func doSomething() {
        self.doSomethingPrivately()
        print("doing something")
    }
}

And then you treat the object as the interface type and not the class/struct type directly.

MyViewController.swift

class MyViewController : UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        MyUtiltyClass.shared.doSomething()
        /*
         //⚠️ compiler error
         MyUtiltyClass.shared.doSomethingPrivately()
         */
    }
}

Happy Coding