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useInfiniteQuery

info
  • Your procedure needs to accept a cursor input of any type
  • 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
import * as trpc from '@trpc/server';
import { Context } from './[trpc]';

export const appRouter = trpc.router<Context>()
.query('infinitePosts', {
input: z.object({
limit: z.number().min(1).max(100).nullish(),
cursor: z.number().nullish(), // <-- "cursor" needs to exist, but can be any type
}),
async resolve({ input }) {
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 | null = null;
if (items.length > limit) {
const nextItem = items.pop()
nextCursor = nextItem!.myCursor;
}

return {
items,
nextCursor,
};
})

Example React Component

components/MyComponent.tsx
import { trpc } from '../utils/trpc';

export function MyComponent() {
const myQuery = trpc.useInfiniteQuery(
[
'infinitePosts',
{
limit: 10,
},
],
{
getNextPageParam: (lastPage) => lastPage.nextCursor,
},
);
// [...]
}

Helpers

getInfiniteQueryData()

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

components/MyComponent.tsx
import { trpc } from '../utils/trpc';

export function MyComponent() {
const utils = trpc.useContext();

const myMutation = trpc.useMutation('infinitePosts.add', {
onMutate({ post }) {
await utils.cancelQuery(['infinitePosts']);
const allPosts = utils.getInfiniteQueryData(['infinitePosts', { limit: 10 }]);
// [...]
}
})
}

setInfiniteQueryData()

This helper allows you to update a queries cached data

components/MyComponent.tsx
import { trpc } from '../utils/trpc';

export function MyComponent() {
const utils = trpc.useContext();

const myMutation = trpc.useMutation('infinitePosts.delete', {
onMutate({ post }) {
await utils.cancelQuery(['infinitePosts']);

utils.setInfiniteQueryData(['infinitePosts', { limit: 10 }], (data) => {
if (!data) {
return {
pages: [],
pageParams: []
}
}

return {
...data,
pages: data.pages.map((page) => {
...page,
items: page.items.filter((item) => item.status === 'published')
})
}
});
}
});

// [...]
}