tRPC Express server with Next.js

Question

As much as I hate this, I am required to use Express for back-end and Next.js for front-end.

I have two Node.js projects, an Express server and a Next.js client.

I did a minimal setup on the back-end side using the Express adapter and it is working fine when i try to hit an endpoint on the browser.

index.ts:
const t = initTRPC.context().create();

export const appRouter = t.router({
  hello: t.procedure.query((opts) = {
    return { message: "Hello World", ctx: opts.ctx.ex.message };
  }),
});

export type AppRouter = typeof appRouter;

app.use(
  "/trpc",
  trpcExpress.createExpressMiddleware({
    router: appRouter,
    createContext,
  })
);

Now when I try to use the trpc client on Next.js I get a  TypeError.

What I did once I created the Next.js client, is running npm link to be able to import my appRouter.

Here is my utils/trpc.ts:

import { httpBatchLink } from "@trpc/client";
import { createTRPCNext } from "@trpc/next";
import { appRouter } from "trpc-express";
function getBaseUrl() {
  if (typeof window !== "undefined") return "";

if (process.env.VERCELURL) return https://${process.env.VERCELURL};

if (process.env.RENDERINTERNALHOSTNAME)
    return http://${process.env.RENDERINTERNALHOSTNAME}:${process.env.PORT};

return http://localhost:${process.env.PORT ?? 3000};
}

export const trpc = createTRPCNext({
  config(opts) {
    return {
      links: [
        httpBatchLink({
          url: ${getBaseUrl()}/api/trpc,

async headers() {
            return {};
          },
        }),
      ],
    };
  },

ssr: false,
});

If any one can provide me with insight regarding this issue, I'd appreciate it.

tRPC Express server with Next.js

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