This project aims to be a base for MVVM projects made with SwiftUI. It downloads some data from SWAPI API and presents it nicely in a SwiftUI list. It also stores some information in CoreData.
The navigation is implemented using a coordinator pattern. Each coordinator (in this case only one) contains a Router used to power the logic of the navigationDestination from NavigationStack.
Using a NavigationDestination struct
Instead of using just an enum for
NavigationDestination, we need to provide an identifier to the route to be able to save the state of the ViewModel. If we don't store the state, we cannot reuse a view of the same type more than one time. Hence the need to use a struct.
Each view contains a Builder that configures the ViewModel with the proper dependencies. This builder is also in charge of storing the state of each ViewModel.
We use a
NSMapTableto avoid memory leaking the ViewModels.
The app is using an MVVM architecture pattern where all of the views logic happens inside the views ViewModel. This means we can decouple the logic (+ navigation) from the view.
Also using a Configurator for each screen allows us to configure and present this view from anywhere in the app.
The app is built using a protocol oriented approach, meaning that almost all of the properties of the objects can be replaced with mocked types. This means that testing the components is very easy.
For example, to test the StarshipsRepository logic, it's very easy to create mocks for LocalDataSourceProtocol, CoreDataManagerProtocol, RemoteDataSourceProtocol and APIClientProtocol.
I like to use the repository pattern to put all of the API/DB related calls inside, meaning that if you want to do something related with Starships, you'll always use StarshipsRepository. This way, if something changes you'll only need to update/change the specific repository and not change anything else from the ViewModel.
The requests to API is very straightforward. A generic APIClient that makes a request to wherever Endpoints. The cool thing is that this APIClient is generic and decodes directly to the Model you asked for.
The endpoints are very easy to use and to extend using enums.