I've home grown a solution for this a couple times... directories of yaml files, where the default is en-US (for those I've worked on). The main set(s) of yaml files are built to path.filename as a prefix to the internal structure in the file... then typescript type(s) are generated from that... with other files then built and assigned the default type as the type. Then checks for errors are run. From there, code generation for server-side usage is done.

It's tended to work relatively well for me.