Migrating from the classic React Client#

Migrating from the classic React Client

From https://trpc.io/docs/client/tanstack-react-query/migrating

There are a few approaches to migrate over, and this library is a significant departure from the classic client, so we're not expecting anybody to do it in one shot. But you will probably want to try a combination of...

Codemod migration#

We're working on a codemod to help you migrate your existing codebase over to the new client. This is already available to try but we need your feedback and contributions to improve it. Codemods are very tricky to get right so we're looking for your help to make it as effective as possible.

Run our upgrade CLI:

npx @trpc/upgrade

When prompted, select the transforms Migrate Hooks to xxxOptions API and Migrate context provider setup.

The CLI refuses to run on a git working tree with uncommitted changes, unless you pass --force. After the transforms it installs @trpc/tanstack-react-query and uninstalls @trpc/react-query, so pass --skipTanstackQuery if you want to keep both while you migrate gradually. It doesn't cover every pattern (useQueries, for example), so typecheck afterwards and migrate whatever is left by hand, using the mappings below.

npx tsc --noEmit

Gradual migration#

The new and classic clients are compatible with each other and can live together in the same application. This means you can start migrating by using the new client in new parts of your application, and gradually migrate over existing usage as you see fit. Most importantly, Query Keys are identical, which means you can use the new client and classic client together and still rely on TanStack Query's caching.

Migrating the provider#

Install the new package, and create its hooks next to the classic ones

npm install @trpc/tanstack-react-query

import { createTRPCReact } from '@trpc/react-query';
import { createTRPCContext } from '@trpc/tanstack-react-query';
import type { AppRouter } from '../server/router';

// Classic, until nothing uses it
export const trpc = createTRPCReact<AppRouter>();

export const { TRPCProvider, useTRPC, useTRPCClient } =
  createTRPCContext<AppRouter>();

The classic trpc.Provider takes the tRPC client as client; TRPCProvider takes it as trpcClient. While both are mounted, give them the same QueryClient and tRPC client, so they share one cache. trpc.createClient() becomes createTRPCClient<AppRouter>() from @trpc/client.

import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import { createTRPCClient, httpBatchLink } from '@trpc/client';
import { useState } from 'react';
import type { AppRouter } from '../server/router';
import { trpc, TRPCProvider } from '../utils/trpc';

export function App(props: { children: React.ReactNode }) {
  const [queryClient] = useState(() => new QueryClient());
  const [trpcClient] = useState(() =>
    createTRPCClient<AppRouter>({
      links: [httpBatchLink({ url: '/api/trpc' })],
    }),
  );

  return (
    <QueryClientProvider client={queryClient}>
      <TRPCProvider trpcClient={trpcClient} queryClient={queryClient}>
        {/* Remove once nothing uses the classic hooks */}
        <trpc.Provider client={trpcClient} queryClient={queryClient}>
          {props.children}
        </trpc.Provider>
      </TRPCProvider>
    </QueryClientProvider>
  );
}

Migrating Queries#

A classic query would look like this

import { trpc } from './trpc';

function Users() {
  const greetingQuery = trpc.greeting.useQuery({ name: 'Jerry' });

  // greetingQuery.data === 'Hello Jerry'
}

and changes to

import { useQuery } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();

  const greetingQuery = useQuery(trpc.greeting.queryOptions({ name: 'Jerry' }));

  // greetingQuery.data === 'Hello Jerry'
}

Migrating Invalidations and other QueryClient usages#

A classic invalidation pattern would look like this

import { trpc } from './trpc';

function Users() {
  const utils = trpc.useUtils();

  async function invalidateGreeting() {
    await utils.greeting.invalidate({ name: 'Jerry' });
  }
}

and changes to

import { useQueryClient } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();
  const queryClient = useQueryClient();

  async function invalidateGreeting() {
    await queryClient.invalidateQueries(
      trpc.greeting.queryFilter({ name: 'Jerry' }),
    );
  }
}

This is the same for any QueryClient usage, instead of using tRPC's useUtils you can now follow the TanStack documentation directly

Migrating Mutations#

A classic mutation might look like this

import { trpc } from './trpc';

function Users() {
  const createUserMutation = trpc.createUser.useMutation();

  createUserMutation.mutate({ name: 'Jerry' });
}

and changes to

import { useMutation } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();

  const createUserMutation = useMutation(trpc.createUser.mutationOptions());

  createUserMutation.mutate({ name: 'Jerry' });
}

Equivalents for the other hooks and useUtils#

Every hook takes the trpc from useTRPC(), and utils becomes const queryClient = useQueryClient(). Here a is a procedure and r a router.

Migrating abortOnUnmount#

The classic integration takes abortOnUnmount when you create the client, which sets the default for every query — an individual query can still override it through its own trpc option

import { createTRPCReact } from '@trpc/react-query';
import type { AppRouter } from './server/router';

export const trpc = createTRPCReact<AppRouter>({
  abortOnUnmount: true,
});

createTRPCContext() takes no options, so there is no global equivalent. Set abortOnUnmount per query instead, in the same trpc option the classic integration uses per request

import { useQuery } from '@tanstack/react-query';
import { useTRPC } from './trpc';

function Users() {
  const trpc = useTRPC();

  const greetingQuery = useQuery(
    trpc.greeting.queryOptions({ name: 'Jerry' }, { trpc: { abortOnUnmount: true } }),
  );
}

Migrating overrides#

createTRPCContext() doesn't take the classic overrides either. To run something after every mutation, such as invalidating the whole cache, use TanStack's own MutationCache callbacks

import { MutationCache, QueryClient } from '@tanstack/react-query';

export const queryClient: QueryClient = new QueryClient({
  mutationCache: new MutationCache({
    onSuccess: () => queryClient.invalidateQueries(),
  }),
});

Common mistakes#

• Destructuring useSuspenseQuery. The classic hook returns [data, query]; TanStack's returns the query, so const [data] = ... becomes const { data } = ....
• Mounting a second QueryClient. While both clients are in use, a separate QueryClient for each provider splits the cache, so an invalidation from one side doesn't refresh queries on the other. Share one.
• Losing @trpc/react-query mid-migration. The upgrade CLI uninstalls it unless you pass --skipTanstackQuery.
• Trusting the codemod blindly. It rewrites the common patterns only. Typecheck after it runs, and check custom wrappers around tRPC hooks by hand.

Related skills#

• react-query-setup (https://trpc.io/docs/client/tanstack-react-query/setup): npx @tanstack/intent@latest load @trpc/tanstack-react-query#react-query-setup