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.proxy.post.byId.useQuery({ 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>
    </>
  );
}