Navigation Using Values

This project demonstrates how one could use values to perform navigation in a similar-ish API to how SwiftUI's new NavigationStack works.

How the API works

Configure the NavigationController

Use the addDestination(for:destination:) API to add handlers for value types. These are typed, so value in this example is always a String.

NavigationController(rootViewController: ViewController())
  .addDestination(for: String.self) { value in
    UIHostingController(rootView: StringView(value: value))
  }      

This acts as a stack where the last definition for a value type wins – for example if another addDestination call occured after this also handling a String type, that latter definition would be used instead.

Send values from view controller

From a view controller (or any responder in the responder chain) you can then call navigate(to:) providing the value you wish to nagivate to.

// Inside a view controller

Button(title: “Show Hello World") {
  self.navigate(to: “Hello World!")
}

Testing

Instead of using Mocks, you could use a proper NavigationController with custom destination handlers to verify that the correct values come out when performing actions.

Implementation Alternatives

Intercepting View Controller

There are alternative methods for handling the destination creation. Another idea might be to have a private view controller that acts as a parent to, but adds the destination creation in the responder chain. In this way, as the call to navigate(to:) goes up the responder chain it can intercepted by one of these destination creator view controllers to create the destination view controller and push that on a vanilla UINavigationController.