Is it possible to check whether an identifier exists in a storyboard before instantiating the object?

Question

In my code I have this line, but I was wondering if there is way to check whether @\"SomeController\" exists before I use it with the \"instantiateViewControllerWit

Answer 1

Swift 4.2.

Declare an extension below.

extension UIStoryboard {
    func instantiateVC(withIdentifier identifier: String) -> UIViewController? {
        // "identifierToNibNameMap" – dont change it. It is a key for searching IDs 
        if let identifiersList = self.value(forKey: "identifierToNibNameMap") as? [String: Any] {
            if identifiersList[identifier] != nil {
                return self.instantiateViewController(withIdentifier: identifier)
            }
        }
        return nil
    }
}

---

Use this methods like this anywhere:

if let viewController = self.storyboard?.instantiateVC(withIdentifier: "yourControllerID") {
            // Use viewController here
            viewController.view.tag = 0; // for example
        }

or

    if let viewController = UIStoryboard(name: "yourStoryboardID", bundle: nil).instantiateVC(withIdentifier: "yourControllerID") {
        // Use viewController here
        viewController.view.tag = 0; // for example
    }

Replace "yourControllerID" with your controller's ID.