trpc-router

Define a router with the router() helper, attach procedures to a domain procedure built from authedProcedure and serverDatabase middleware, validate inputs with zod schemas, and return { data, success: true } for queries or { data, message, success: true } for mutations.

Use middleware chained after serverDatabase that returns opts.next with models constructed from ctx.serverDB and ctx.userId added to ctx. Procedures then access ctx.fooModel directly instead of instantiating models inside each handler.

Only when the model needs a different userId than the current context, such as a watchdog iterating over multiple users' tasks. Otherwise always inject models through middleware to keep procedures clean and consistent.

Re-throw existing TRPCError instances unchanged, and wrap other errors by logging with console.error using a [domain:procedure] prefix, then throwing a new TRPCError with code INTERNAL_SERVER_ERROR and the original error as cause.

Create a single aggregated detail procedure that resolves the main entity, then fetches children and related records in parallel with Promise.all. This returns one combined payload so the frontend avoids N sequential requests.