Fetch API Adapter for tRPC

Proof of concept Fetch API adapter for tRPC. This allows you to deploy tRPC endoints to Remix routes and possibly to other systems using the Fetch API

By "Fetch API" we mean systems that implement the Request and Response objects specified in the Fetch Standard such as Remix, CloudFlare Workers, Deno and Service Workers. This is some times refered as "The Web Platform". This adapter should allow to deploy tRPC on all these systems but in practice it is bit tricky since tRPC has some hard dependencies on Node.js but there are workarounds.

This implementation is very basic. No batching support and error handling might be bit lacking. But it does support queries, mutations and request contexts.

Hopefully we can see this implemented in tRPC core some day. Here's a tracking issue https://github.com/trpc/trpc/issues/1374

Install

npm install @valu/trpc-fetch-api-adapter

Usage in Remix

Create a route file to app/routes/trpc/$.ts with a tRPC router:

import * as trpc from "@trpc/server";
import type { ActionFunction } from "remix";
import { createFetchAPIHandler } from "@valu/trpc-fetch-api-adapter";

interface MyContext {}

export const appRouter = trpc.router<MyContext>().query("hello", {
    resolve() {
        return {
            greeting: "Hello Remix",
        };
    },
});

export type AppRouter = typeof appRouter;

const handler = createFetchAPIHandler({
    router: appRouter,
    async createContext(req): Promise<MyContext> {
        return {};
    },
});

// Handle GET requests like /trpc/hello
export const loader: LoaderFunction = async ({ request }) => {
    return await handler(request);
};

// POST request are actions in Remix so we need to add different handler for it
export const action: ActionFunction = async ({ request }) => {
    return await handler(request);
};

And create a client without batching

import { createTRPCClient } from "@trpc/client";
import { httpLink } from "@trpc/client/links/httpLink";

import type { AppRouter } from "./routes/trpc/$";

const client = createTRPCClient<AppRouter>({
    links: [
        httpLink({
            url: "http://localhost:3000/trpc",
        }),
    ],
});

Usage in CloudFlare Workers

Full example here https://github.com/esamattis/trpc-cloudflare-worker

import * as trpc from "@trpc/server";";
import { createFetchAPIHandler } from "@valu/trpc-fetch-api-adapter";

export const appRouter = trpc.router<MyContext>().query("hello", {
    resolve() {
        return {
            greeting: "Hello from CloudFlare",
        };
    },
});

const handler = createFetchAPIHandler({ router: appRouter });

addEventListener("fetch", async (event) => {
    event.respondWith(handler(event.request));
});