useInfiniteQuery

info

• Your procedure needs to accept a cursor input of any type (string, number, etc) to expose this hook.
• For more details on infinite queries read the react-query docs
• In this example we're using Prisma - see their docs on cursor-based pagination

Example Procedure

server/routers/_app.ts
tsx
import { initTRPC } from '@trpc/server';
import { z } from 'zod';
import { Context } from './[trpc]';
export const t = initTRPC.create();
export const appRouter = t.router({
  infinitePosts: t.procedure
    .input(
      z.object({
        limit: z.number().min(1).max(100).nullish(),
        cursor: z.number().nullish(), // <-- "cursor" needs to exist, but can be any type
      }),
    )
    .query(async (opts) => {
      const { input } = opts;
      const limit = input.limit ?? 50;
      const { cursor } = input;
      const items = await prisma.post.findMany({
        take: limit + 1, // get an extra item at the end which we'll use as next cursor
        where: {
          title: {
            contains: 'Prisma' /* Optional filter */,
          },
        },
        cursor: cursor ? { myCursor: cursor } : undefined,
        orderBy: {
          myCursor: 'asc',
        },
      });
      let nextCursor: typeof cursor | undefined = undefined;
      if (items.length > limit) {
        const nextItem = items.pop();
        nextCursor = nextItem!.myCursor;
      }
      return {
        items,
        nextCursor,
      };
    }),
});

server/routers/_app.ts
tsx
import { initTRPC } from '@trpc/server';
import { z } from 'zod';
import { Context } from './[trpc]';
export const t = initTRPC.create();
export const appRouter = t.router({
  infinitePosts: t.procedure
    .input(
      z.object({
        limit: z.number().min(1).max(100).nullish(),
        cursor: z.number().nullish(), // <-- "cursor" needs to exist, but can be any type
      }),
    )
    .query(async (opts) => {
      const { input } = opts;
      const limit = input.limit ?? 50;
      const { cursor } = input;
      const items = await prisma.post.findMany({
        take: limit + 1, // get an extra item at the end which we'll use as next cursor
        where: {
          title: {
            contains: 'Prisma' /* Optional filter */,
          },
        },
        cursor: cursor ? { myCursor: cursor } : undefined,
        orderBy: {
          myCursor: 'asc',
        },
      });
      let nextCursor: typeof cursor | undefined = undefined;
      if (items.length > limit) {
        const nextItem = items.pop();
        nextCursor = nextItem!.myCursor;
      }
      return {
        items,
        nextCursor,
      };
    }),
});

Example React Component

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const myQuery = trpc.infinitePosts.useInfiniteQuery(
    {
      limit: 10,
    },
    {
      getNextPageParam: (lastPage) => lastPage.nextCursor,
      // initialCursor: 1, // <-- optional you can pass an initialCursor
    },
  );
  // [...]
}

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const myQuery = trpc.infinitePosts.useInfiniteQuery(
    {
      limit: 10,
    },
    {
      getNextPageParam: (lastPage) => lastPage.nextCursor,
      // initialCursor: 1, // <-- optional you can pass an initialCursor
    },
  );
  // [...]
}

Helpers

getInfiniteData()

This helper gets the currently cached data from an existing infinite query

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const utils = trpc.useUtils();
  const myMutation = trpc.infinitePosts.add.useMutation({
    async onMutate(opts) {
      await utils.infinitePosts.cancel();
      const allPosts = utils.infinitePosts.getInfiniteData({ limit: 10 });
      // [...]
    },
  });
}

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const utils = trpc.useUtils();
  const myMutation = trpc.infinitePosts.add.useMutation({
    async onMutate(opts) {
      await utils.infinitePosts.cancel();
      const allPosts = utils.infinitePosts.getInfiniteData({ limit: 10 });
      // [...]
    },
  });
}

setInfiniteData()

This helper allows you to update a query's cached data

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const utils = trpc.useUtils();
  const myMutation = trpc.infinitePosts.delete.useMutation({
    async onMutate(opts) {
      await utils.infinitePosts.cancel();
      utils.infinitePosts.setInfiniteData({ limit: 10 }, (data) => {
        if (!data) {
          return {
            pages: [],
            pageParams: [],
          };
        }
        return {
          ...data,
          pages: data.pages.map((page) => ({
            ...page,
            items: page.items.filter((item) => item.status === 'published'),
          })),
        };
      });
    },
  });
  // [...]
}

components/MyComponent.tsx
tsx
import { trpc } from '../utils/trpc';
export function MyComponent() {
  const utils = trpc.useUtils();
  const myMutation = trpc.infinitePosts.delete.useMutation({
    async onMutate(opts) {
      await utils.infinitePosts.cancel();
      utils.infinitePosts.setInfiniteData({ limit: 10 }, (data) => {
        if (!data) {
          return {
            pages: [],
            pageParams: [],
          };
        }
        return {
          ...data,
          pages: data.pages.map((page) => ({
            ...page,
            items: page.items.filter((item) => item.status === 'published'),
          })),
        };
      });
    },
  });
  // [...]
}