"Simulator" as an additional context

[pieterjongsma]

I'm using the Dependencies library to control my WatchConnectivity dependency. This is working great in previews and testing. When running in the Simulator, the Dependencies library will of course pick the liveValue. However, there are some functions in WatchConnectivity that do not work in the simulator, like transferring files. This breaks a lot of functionality in my app. I was wondering if I could use the Dependencies library to use a mock implementation for those specific functions.

Is there a way to overwrite dependencies when running in the simulator using withDependencies or another function? I've tried using it in App.init, but this affects how I can set the App's instance variables (can no longer assign to let).

If not, would you consider adding the simulator as an additional context in the Dependencies source code (defaulting to liveValue)? I would be happy to try my hand at the implementation.

[mbrandonw]

Hi @pieterjongsma, there are two ways you can handle this in the library today. In your entry point you can override any dependencies a single time, globally, using prepareDependencies:

@main 
struct MyApp: App {
  init() {
    #if TARGET_IPHONE_SIMULATOR
      prepareDependencies {
        $0.client = MockClick()
      }
    #endif 
  }

  …
}

Or you can perform this TARGET_IPHONE_SIMULATOR check directly for your liveValue:

struct Client: DependencyKey {
  #if TARGET_IPHONE_SIMULATOR 
    static var liveValue: Client { … }
  #else 
    static var liveValue: Client { … }
  #endif 
}

[pieterjongsma]

@mbrandonw Ah, thank you! prepareDependencies was what I was looking for.

Out of curiosity: you don't think a special value for the simulator has a place in the library, just like previewValue has now?