The demo needs to be fleshed out. It serves as a sanity check / ad hoc test suite, but I don't have much time for this project since I became a dad. If you want to help, let me know!
See the demo here: https://hejfelix.github.io/slinky-wrappers/
See in build.sbt how the demo project is set up using scalajs-bundler. For a bigger example using material ui, please see this project: https://github.com/hejfelix/wishr
These are wrappers that I'm writing for my own projects. Currently, there's somewhat more support for Material UI than Semantic UI. There's an example using it here: https://github.com/hejfelix/wishr
There are some things which are very difficult to model using Scala's type system. Many of these problems could potentially be fixed by Dotty (singleton types, intersection-/union types, proper enums).
Furthermore, the intellij support is not (IMHO) amazing when using the @react macro. Hence, I'm not too busy with this project.