When using Babel 7 with the new decorators plugin, the @prop decorators are ignored. This is also the case when using the Babel TypeScript plugin (like is the case with Create react app 2 and Next.js 7 with the TypeScript plugin).

Current workaround is described in the setup guide.

I'm working on a few ideas for a permanent workaround, but if you have any ideas how to address this, feel free to contact me.