Example app​

Description

Links

Express server & procedure calls with Node.js.

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How to add tRPC to existing Express project​

1. Install deps​

bash

yarn add @trpc/server zod

Zod isn't a required dependency, but it's used in the sample router below.

2. Create a tRPC router​

Implement your tRPC router. A sample router is given below:

server.ts

ts

import { initTRPC } from '@trpc/server';

import { z } from 'zod';

export const t = initTRPC.create();

export const appRouter = t.router({

getUser: t.procedure.input(z.string()).query((opts) => {

`opts.input; // string`

`return { id: opts.input, name: 'Bilbo' };`

}),

createUser: t.procedure

`.input(z.object({ name: z.string().min(5) }))`

`.mutation(async (opts) => {`

  `// use your ORM of choice`

  `return await UserModel.create({`

    `data: opts.input,`

  `});`

`}),`

});

// export type definition of API

export type AppRouter = typeof appRouter;

If your router file starts getting too big, split your router into several subrouters each implemented in its own file. Then merge them into a single root appRouter.

3. Use the Express adapter​

tRPC includes an adapter for Express out of the box. This adapter lets you convert your tRPC router into an Express middleware.

server.ts

ts

import { initTRPC } from '@trpc/server';

import * as trpcExpress from '@trpc/server/adapters/express';

// created for each request

const createContext = ({

req,

res,

}: trpcExpress.CreateExpressContextOptions) => ({}); // no context

type Context = Awaited<ReturnType<typeof createContext>>;

const t = initTRPC.context<Context>().create();

const appRouter = t.router({

// [...]

});

const app = express();

app.use(

'/trpc',

trpcExpress.createExpressMiddleware({

`router: appRouter,`

`createContext,`

}),

);

app.listen(4000);

Your endpoints are now available via HTTP!

Endpoint

HTTP URI

getUser

GET http://localhost:4000/trpc/getUser?input=INPUT

where INPUT is a URI-encoded JSON string.

createUser

POST http://localhost:4000/trpc/createUser

with req.body of type {name: string}