The Fruta sample code provides a good example of a project structure that supports multi-platforms.
Use Group as Folder
Every group in Xcode is an actual folder.
Stop using logical groups without folder.
The Main Groups
- Shared
- iOS
- iOS Clip
- iOS Widgets
- macOS
- macOS Widgets
- Packages
- Playgrounds
Platforms & extensions have their own group. Within them, structure as per your selected architecture eg. MVVM, VIPER. Or any logical grouping that makes the most sense.
Shared Code
The Shared group is for code used in all platforms. In Fruta, almost all the code is under Shared. Only few Swift files are in the platform specific group.
Even the @main App is in Shared, and it runs for all: iOS, macOS, widgets, clips. It works because it uses preprocessor code. Alternatively, we could create specific Swift file for each platform.
You can even breakdown further eg. Shared-iOS. It is up to you as needed.
Packages
Local packages within the projects. Eg. Fruta-Networking. This is also shared code, but in a formal self contained package. Later on, they can also be moved out of the project to become an external dependency.
These packages are selectively added to the targets; they can be excluded in a certain target.
Use of Preprocessor Code
Aka Active Compilation Conditions (NEW!) under build settings. Yet not exactly new, since before this, we already have been adding to Other Swift Flags.
With that, we can write preprocessors such as #if APPCLIP, or #if ENABLE_DANCE_MONKEY_FEATURE.
We can also use #if os(iOS) etc.
Playgrounds
Playground is a scratchpad. Nice to try out some codes, or even to explain certain concepts.
Tests
The Fruta project did not tests. Generally, you have 2 types of tests:
- Unit Testing
- UI Testing
Therefore each platform will have to create 2 test targets eg. FrutaiOSUnitTests, FrutaiOSUITests.
That’s a lot of tests, if you’re testing 😄