Beeline is a very small library that aims to provide a lean, automatic implementation of the classic iOS router pattern. It extends UIViewController to retain a Router object that serves as the source of truth for controlling navigation flows for all of the view controller's children. When a child view controller wishes to transition to a new screen, it can call show() on itself and this request is passed up the view controller chain to the routing view controller.

A very basic custom implementation looks as the following. First, we create a Swift enum conforming to Route where we can define the types of destinations with which we want to move:

enum AppRoute: Route {
    case viewController(number: Int)
}

Thanks to Swift associated enums, we can also include any custom parameters the new destination may need.

We then also make a new class which subclasses Router, which serves as our single point of truth for controlling the app flow based off the destinations we defined above:

public class AppRouter: Router {
    override func show(_ route: Route,
                        from sourceViewController: UIViewController?) -> Bool {

        // Optionally, filter out routes we don't support
        guard let appRoute = route as? AppRoute else { return false }

        // Check the requested enum, and perform the transition
        switch appRoute {
        case .viewController(let number):
            let newViewController = ViewController(number: number)
            sourceViewController?
                .navigationController?
                .pushViewController(newViewController, animated: true)
        }

        return true
    }
}

Using Objective-C associated objects, we can assign this router to any parent view controller that contains all of the view controllers that might want to perform these transitions:

let navigationController = UINavigationController(rootViewController: ViewController())
navigationController.router = AppRouter()

Finally, without any further modification to any of the child view controllers, they can start a transition by simply calling show() with the desired destination:

class ViewController: UIViewController {
    func moveToNewViewController() {
        show(AppRoute.viewController(number: 2))
    } 
} 

And that's the entire library! 🎉

• Swift 5
• UIKit-compatible platforms (iOS, tvOS, Mac Catalyst)

Beeline is a very small framework, with all of its code contained in Router.swift. You can install it in the following ways:

Drag the Beeline/Router.swift file into your Xcode project.

pod 'Beeline'

You can add Beeline to an Xcode project by adding it as a package dependency.

https://github.com/TimOliver/Beeline

or, add the following to the dependencies in package.swift.

dependencies: [
  .package(url: "https://github.com/TimOliver/Beeline", from: "1.0.2")
]

No plans to support Carthage at the moment, but please consider filing a PR if you would like it!

Beeline was built as a component of iComics 2 by Tim Oliver

Beeline is available under the MIT License. Please check the LICENSE file for more information.