Closes #

The goal

Move the middleware abstraction and the base of the procedure builder out of tRPC so other libraries can leverage it

Usecases

Create a base trpc middleware lib

• a future RSC-only library it and only add e.g. .actions() and to make a safe data layer
• a standalone app can use middleware instead of e.g. a express middleware
• @trpc/server can use it and add .query() / .mutation() etc

The how

🚧 The real way of doing this should likely be done like how redux toolkit does it

Right now - I've mainly cared about the types

• I've created a middleware.ts that is the "base module"
• Trying to work out how middlewareExtend.test.ts could extend the base module and inject options into the middleware chain and new builder methods without polluting the global scope

modules.test.ts is a start of a builder that can be extended by libraries

References

The principle should be possible: https://x.com/eskimojo/status/1837827507795501323