Suggested structure
Here's how you could structure the tRPC-related files in a non-trivial application in order to avoid cyclic dependencies:
--------------
| lib/trpc | 👈 place your tRPC-related stuff here
--------------
|
|-- context.ts 👈 router context
|-- t.ts 👈 tRPC definition helper (see below)
|-- router.ts 👈 main router definition (imports files defined in routes folder)
|-- middleware.ts 👈 tRPC middleware (this could be split into multiple files if necessary)
|-- client.ts 👈 define a client helper function here
|
| ------------
|--| routes | 👈 split your routes into multiple files and place them here
| ------------
| |
| |-- route-1.ts
| |-- route-2.ts
| |-- route-3.ts
| | ...
| |-- route-n.ts
|
| ----------------
|--| middleware | 👈 split your middleware into multiple files and place them here
----------------
|
|-- middleware-1.ts
| ...
|-- middleware-n.ts
The t.ts file contains a simple helper that allows you to build routes and middleware:
lib/trpc/t.ts
import type { Context } from '$lib/trpc/context';
import { initTRPC } from '@trpc/server';
import transformer from 'trpc-transformer';
export const t = initTRPC.context<Context>().create({ transformer });
You'll have to import t.ts in multiple other files such as router.ts,
middleware.ts,
routes/route-1.ts, routes/route-2.ts, etc.