A question I didn't get to ask while there is -- will there be some sort of type sharing system introduced?
I've been a user of both Typescript and Flow (both great tools), but saw Typescript's popularity soar because of community written types.
Yes. This was one of goals of our talks. We wanted implementors of type systems for ruby to start collaborating, in particular on a repository of typed shims.
The details of how this would work out might be different. Typescript and Flow change syntax and thus they cannot be included inline in arbitrary JavaScript libraries. We're intentionally compatible with Ruby syntax. Thus we would like this "repository of types for libraries" to only contain types intermittently, until types have been accepted to upstream of respective library.
I see. Do you see this being a mono-repo of types that's under a Sorbet org or something Sorbet looks for in a gem if provided? Opening issues for a project's types with Typescript has been somewhat painful since many live in one repo [1].