Swift is a strongly typed language. A good practice is to replace the strings that serve as identifiers in UIKit with some proper Swift types.

Storyboard identifiers

Storyboards lets you instantiate your view controller with a specific identifier. This identifier is a unique string.

The problem with that is that you can have a wrong or obsolete identifiers. Furthermore Swift is a strongly typed language so it would be nice to also have the precise type of the view controller, instead of a generic UIViewController.

There is precisely, a great tool for this task, SwiftGen. The punchline for this tool is :

The Swift code generator for your assets, storyboards, Localizable.strings, … — Get rid of all String-based APIs!

For instructional purpose, and because my app is small, here is how I achieve the same result with a simple class:

struct MainStoryboard {
    
    static var storyboard: UIStoryboard {
        let bundle = Bundle.main
        return UIStoryboard(name: "Main", bundle: bundle)
    }
    
    static var masterViewController: MasterViewController {
        return storyboard.instantiateViewController(withIdentifier: "master-scene") as! MasterViewController
    }
    
    static var detailViewController: DetailViewController {
        return storyboard.instantiateViewController(withIdentifier: "detail-scene") as! DetailViewController
    }
    
    static var imageViewController: ImageViewController {
        return storyboard.instantiateViewController(withIdentifier: "image-scene") as! ImageViewController
    }
    
    static var settingsViewController: UIViewController {
        return storyboard.instantiateViewController(withIdentifier: "settings-navigation")
    }
}