tRPC

v.change("2026-05-14", {
  describe: "user.name split into firstName/lastName",
  routes: ["GET /users", "GET /users/:id", "POST /users"],
  procedures: ["demo.userList", "demo.userCreate"],   // same change, both transports
  request:  { up:   (body: UserCreateV1): UserCreate => splitName(body) },
  response: { down: (body: User | User[]): UserV1 | UserV1[] => ... },
});

// context.ts — 1. stash the resolve inputs on the tRPC context
import { versionlessContext, type VersionlessContext } from "@versionless/adapter-trpc";
import { v } from "./versionless";

export async function createContext({ req }: { req: Request }) {
  return {
    // ...your auth/session fields...
    ...versionlessContext(v, { req }),
  };
}
export type Context = Awaited<ReturnType<typeof createContext>>;

// trpc.ts — 2. error formatter, 3. the procedure middleware
import { initTRPC } from "@trpc/server";
import { versionlessErrorFormatter, versionlessMiddleware } from "@versionless/adapter-trpc";
import type { Context } from "./context";
import { v } from "./versionless";

export const t = initTRPC.context<Context>().create({
  errorFormatter: versionlessErrorFormatter(v),   // error shapes are versioned too
});

export const router = t.router;
export const publicProcedure = t.procedure;

// Attach BEFORE .input(...) so up() runs pre-validation.
export const versionedProcedure = publicProcedure.use(versionlessMiddleware());

// routers/demo.ts — procedures speak the current shape only
import { z } from "zod";
import { userCreateSchema, userSchema } from "./schema";

export const demoRouter = router({
  userList: versionedProcedure.output(z.array(userSchema)).query(() => users),
  userCreate: versionedProcedure
    .input(userCreateSchema)
    .output(userSchema)
    .mutation(({ input }) => addUser(input)),
});

// server — 4. sunset headers on the HTTP envelope
import { fetchRequestHandler } from "@trpc/server/adapters/fetch";
import { versionlessResponseMeta } from "@versionless/adapter-trpc";

fetchRequestHandler({
  endpoint: "/trpc",
  router: appRouter,
  req: request,
  createContext,
  responseMeta: versionlessResponseMeta(v),
});