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SSG Helpers

createSSGHelpers providers you a set of helper functions that you can use to prefetch queries on the server.

import { createSSGHelpers } from '@trpc/react/ssg';

const {
prefetchQuery,
prefetchInfiniteQuery,
fetchQuery,
fetchInfiniteQuery,
dehydrate,
queryClient,
} = await createSSGHelpers({
router: appRouter,
ctx: createContext,
transformer: superjson, // optional - adds superjson serialization
});

The returned functions are all wrappers around react-query functions. Please check out their docs to learn more about them.

Next.js Example

pages/posts/[id].tsx
import { createSSGHelpers } from '@trpc/react/ssg';
import { GetServerSidePropsContext, InferGetServerSidePropsType } from 'next';
import { prisma } from 'server/context';
import { appRouter } from 'server/routers/_app';
import { trpc } from 'utils/trpc';
import superjson from 'superjson';

export async function getServerSideProps(
context: GetServerSidePropsContext<{ id: string }>,
) {
const ssg = await createSSGHelpers({
router: appRouter,
ctx: {},
transformer: superjson,
});
const id = context.params?.id as string;

// Prefetch `post.byId`
await ssg.fetchQuery('post.byId', {
id,
});

// Make sure to return { props: { trpcState: ssg.dehydrate() } }
return {
props: {
trpcState: ssg.dehydrate(),
id,
},
};
}

export default function PostViewPage(
props: InferGetServerSidePropsType<typeof getServerSideProps>,
) {
const { id } = props;

// This query will be immediately available as it's prefetched.
const postQuery = trpc.useQuery(['post.byId', { id }]);

const { data } = postQuery;

return (
<>
<h1>{data.title}</h1>
<em>Created {data.createdAt.toLocaleDateString()}</em>

<p>{data.text}</p>

<h2>Raw data:</h2>
<pre>{JSON.stringify(data, null, 4)}</pre>
</>
);
}