Support for the "Darwin" sub-platform of the Island target is in the works for a future update and currently in early preview. This includes support for macOS, iOS, tvOS and watchOS.
Medium-term, Island/Darwin mod eis going to replace the dedicated "Toffee" compiler mode for Cocoa, by supporting both native Island objects, Cocoa objects and Apple Swift objects in the same project space. U can read more about this in thetopic.
- Current Toffee platform for Cocoa