React Query: Overview of useInfiniteQuery

React Query's useInfiniteQuery hook is a powerful tool for efficiently loading and displaying large sets of data, page by page, in a React application. Unlike traditional pagination, infinite query seamlessly fetches data as the user scrolls, enhancing user experience and performance.

Understanding useInfiniteQuery

What is useInfiniteQuery in React Query?

useInfiniteQuery is a hook provided by React Query that allows you to fetch data in paginated form. It's ideal for scenarios like infinite scrolling, where data loads as the user reaches the bottom of a list or a page.

What are the key features of useInfiniteQuery?

• Automatic pagination: Manages the pagination logic, reducing the need to manually handle page numbers.
• Background data fetching: Updates data in the background, ensuring a fresh user interface.
• Cache and state management: Efficiently caches data and manages the loading, error, and success states.

How to set up useInfiniteQuery

Import the hook

First, import useInfiniteQuery from React Query.

import { useInfiniteQuery } from 'react-query';

Define the fetching function

Define a fetching function that takes a page parameter and returns a promise. This function is where you call your API or data source.

const fetchProjects = ({ pageParam = 1 }) => {
  return fetch(`/api/projects?page=${pageParam}`).then(res => res.json());
};

Use the hook

Implement useInfiniteQuery in your component. Pass the key and the fetching function, along with options like getNextPageParam to handle the pagination logic.

const { data, fetchNextPage, hasNextPage } = useInfiniteQuery(
  'projects',
  fetchProjects,
  {
    getNextPageParam: (lastPage, pages) => lastPage.nextPage
  }
);

How to implememnt infinite loading

Rendering data

Use the data.pages array to render your list. Each element in this array corresponds to a fetched page of data.

data.pages.map((page, i) => (
  <React.Fragment key={i}>
    {page.projects.map(project => <ProjectCard key={project.id} project={project} />)}
  </React.Fragment>
));

Fetching next page

Trigger fetchNextPage when the user scrolls near the bottom of the list or when a 'Load More' button is clicked.

<button onClick={() => fetchNextPage()} disabled={!hasNextPage}>
  Load More
</button>

Observing scroll position

You can use libraries like react-intersection-observer to call fetchNextPage automatically as the user scrolls.

Error and loading states

Handling loading state

React Query provides isLoading and isFetchingNextPage states to indicate loading status.

if (isLoading) return <div>Loading...</div>;

Handling errors

Use the isError and error states to display error messages.

if (isError) return <div>Error: {error.message}</div>;

Tips for performance optimization

Data caching

React Query automatically caches your data, reducing the number of requests and improving performance.

Stale time configuration

Configure staleTime to control how frequently React Query refetches data, balancing between data freshness and performance.

Windowing libraries

For extremely long lists, consider using windowing libraries like react-window to render only visible items, enhancing performance.