MVMUM Architecture (i.e. View ViewModel UseCase Model)

MVMUM.swift

MVMUM Architecture (View ViewModel UseCase Model)
V > VM > UC > M  ( i.e. direction of dependency)
<= direct of flow control
=> increasing relevant to domain (i.e. plain object)
<= increasing relevant to framework/environment (i.e. platform objects with side effect e.g. native GUI, database)



Example: (user login screen)

// View. UI event handling, layout.
class LoginView {
  var viewModel: LoginViewModel 
  var loginButton = UIButton()

   func viewDidLoad() {
       viewModel =  ViewModelFactory.newLoginViewModel(context)
      …
    }
}

// View model. Display formatting and navigation logics here.

enum Route {
 case presentSuccessLogined
 case forgetPasswordFlow
}

class LoginViewModel {
 var useCase: LoginUseCase
 var prefilledName
 var localizedErrorMessage

 var onLoadingIndicatorVisible: (Bool) -> Void
 var onSubmitButtonEnabled: (Bool) -> Void
 var onPromptError: () -> Void
 var onNavigateTo: (Route) -> Void

 init(context) {
   useCase = UseCaseFactory.newLoginUseCase(context)
 }
}

// Platform independent UseCase. All business logics here.

class LoginUseCase {
 var session: SessionModel
 var username
 var password

 func login()
 func setUsername()
 func setPassword()

 var onLoading: (Bool) -> Void
 var onError: (String) -> Void
 var onSuccess: (SessionModel) -> Void
}

// Plain object Model. Entity only.

class SessionModel {
 var userId
 var sessionToken
 var expiryTime
}