Usage with React

info

• If you're using Next.js, read the Usage with Next.js guide instead.
• In order to infer types from your Node.js backend you should have the frontend & backend in the same monorepo.

Add tRPC to existing React project

tRPC works fine with Create React App!

1. Install tRPC dependencies

yarn add @trpc/client @trpc/server @trpc/react react-query zod

• React Query: @trpc/react provides a thin wrapper over react-query. It is required as a peer dependency.
• Zod: most examples use Zod for input validation and we highly recommended it, though it isn't required. You can use a validation library of your choice (Yup, Superstruct, io-ts, etc). In fact, any object containing a parse, create or validateSync method will work.

2. Enable strict mode

If you want to use Zod for input validation, make sure you have enabled strict mode in your tsconfig.json:

// tsconfig.json
{
  // ...
  "compilerOptions": {
    // ...
    "strict": true
  }
}

If strict mode is too much, at least enable strictNullChecks:

// tsconfig.json
{
  // ...
  "compilerOptions": {
    // ...
    "strictNullChecks": true
  }
}

3. Implement your appRouter

Follow the Quickstart and read the @trpc/server docs for guidance on this. Once you have your API implemented and listening via HTTP, continue to the next step.

4. Create tRPC hooks

Create a set of strongly-typed React hooks from your AppRouter type signature with createReactQueryHooks.

// utils/trpc.ts
import { createReactQueryHooks } from '@trpc/react';
import type { AppRouter } from '../path/to/router.ts';

export const trpc = createReactQueryHooks<AppRouter>();
// => { useQuery: ..., useMutation: ...}

5. Add tRPC providers

In your App.tsx

import React from 'react';
import { useState } from 'react';
import { QueryClient, QueryClientProvider } from 'react-query';
import { trpc } from './utils/trpc';

function App() {
  const [queryClient] = useState(() => new QueryClient());
  const [trpcClient] = useState(() =>
    trpc.createClient({
      url: 'http://localhost:5000/trpc',

      // optional
      headers() {
        return {
          authorization: getAuthCookie(),
        };
      },
    }),
  );
  return (
    <trpc.Provider client={trpcClient} queryClient={queryClient}>
      <QueryClientProvider client={queryClient}>
        {/* Your app here */}
      </QueryClientProvider>
    </trpc.Provider>
  );
}

6. Fetch data

import { trpc } from '../utils/trpc';

const IndexPage = () => {
  const hello = trpc.useQuery(['hello', { text: 'client' }]);
  if (!hello.data) return <div>Loading...</div>;
  return (
    <div>
      <p>{hello.data.greeting}</p>
    </div>
  );
};

export default IndexPage;