tRPC

End-to-end typesafe APIs made easy

trpc-svelte-query

A tRPC wrapper around @tanstack/svelte-query.

Installation

# pnpm
pnpm add trpc-svelte-query @tanstack/svelte-query

# Yarn
yarn add trpc-svelte-query @tanstack/svelte-query

# npm
npm install trpc-svelte-query @tanstack/svelte-query

Basic Example

Set up tRPC in lib/trpc/index.ts

import { createTRPCSvelte, httpBatchLink } from 'trpc-svelte-query';
// Import the router type from your server file
import type { AppRouter } from '$lib/server/routes/_app';

export const trpc = createTRPCSvelte<AppRouter>({
  links: [
    httpBatchLink({
      url: '/api/trpc',
    }),
  ],
});

Set up @tanstack/svelte-query's provider in your root layout.

<script lang="ts">
  import { QueryClientProvider } from '@tanstack/svelte-query';
  import { trpc } from '$lib/trpc/client';
</script>

<QueryClientProvider client={trpc.queryClient}>
  <slot />
</QueryClientProvider>

Set up your API handler in routes/api/trpc/[...trpc]/+server.ts

import { createTRPCSvelteServer } from 'trpc-svelte-query/server';
import { appRouter } from '$lib/server/routes/_app';

const trpcServer = createTRPCSvelteServer({
  endpoint: '/api/trpc',
  router: appRouter,
});

export const GET = trpcServer.handler;
export const POST = trpcServer.handler;

Now in any component, you can query your API using the client you created.

<script lang="ts">
  import { trpc } from '$lib/trpc/client';

  const query = trpc.greeting.query({ name: 'tRPC' });
</script>

{#if $query.isSuccess}
  <p>{$query.data.greeting}</p>
{:else if $query.isError}
  <p>{$query.error.message}</p>
{:else}
  <p>Loading...</p>
{/if}

SSR with SvelteKit

Extract your trpcServer instance into its own file (i.e. $lib/server/server). You'll use this object to handle SSR.

import { createTRPCSvelteServer } from 'trpc-svelte-query/server';
import { appRouter } from '$lib/server/routes/_app';

export const trpcServer = createTRPCSvelteServer({
  endpoint: '/api/trpc',
  router: appRouter,
});

Use that instance in your api endpoint:

import { trpcServer } from '$lib/server/server';

export const GET = trpcServer.handler;
export const POST = trpcServer.handler;

Add a root +layout.server.ts to pass SSR data from the server to the client.

import { trpcServer } from '$lib/server/server';
import type { LayoutServerLoad } from './$types';

export const load: LayoutServerLoad = async (event) => {
  return {
    trpc: trpcServer.hydrateToClient(event),
  };
};

Update your root layout to hydrate that SSR data.

<script lang="ts">
  import { trpc } from '$lib/trpc/client';
  import { QueryClientProvider } from '@tanstack/svelte-query';
  import type { LayoutData } from './$types';

  export let data: LayoutData;

  $: queryClient = trpc.hydrateFromServer(data.trpc);
</script>

<QueryClientProvider client={queryClient}>
  <slot />
</QueryClientProvider>

Add a +page.server.ts file to preload specific queries.

import { trpc } from '$lib/server/server';
import type { PageServerLoad } from './$types';

export const load: PageServerLoad = async (event) => {
  await trpcServer.greeting.ssr({ name: 'tRPC' }, event);
};