React Query is a powerful tool that simplifies data fetching in React applications. It provides hooks to manage server-state, caching, and synchronization, making it easier to handle asynchronous operations.

Benefits of Using React Query

• Simplified Data Fetching: React Query abstracts the complexities of data fetching, allowing developers to focus on building features.
• Automatic Caching: It caches data by default, reducing the number of network requests and improving performance.
• Background Data Synchronization: React Query keeps data up-to-date by refetching in the background when necessary.
• Pagination and Infinite Queries: It offers built-in support for paginated and infinite scrolling data.
• Optimistic Updates: You can update the UI immediately while the server request is in progress.
• Error Handling: Built-in error handling and retry mechanisms.

Getting Started with React Query

To start using React Query, install it via npm:

bash
1npm install @tanstack/react-query

Then, wrap your application with the QueryClientProvider:

jsx
1import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
2
3const queryClient = new QueryClient();
4
5function App() {
6  return (
7    <QueryClientProvider client={queryClient}>
8      {/* Your application components */}
9    </QueryClientProvider>
10  );
11}

Basic Usage

Now, you can use the useQuery hook to fetch data:

jsx
1import { useQuery } from '@tanstack/react-query';
2
3function Posts() {
4  const { data, error, isLoading } = useQuery({
5    queryKey: ['posts'],
6    queryFn: fetchPosts
7  });
8
9  if (isLoading) return <div>Loading...</div>;
10  if (error) return <div>Error loading posts</div>;
11
12  return (
13    <ul>
14      {data.map(post => (
15        <li key={post.id}>{post.title}</li>
16      ))}
17    </ul>
18  );
19}

Advanced Features

Mutations

For creating, updating, or deleting data:

jsx
1import { useMutation, useQueryClient } from '@tanstack/react-query';
2
3function CreatePost() {
4  const queryClient = useQueryClient();
5  
6  const mutation = useMutation({
7    mutationFn: createPost,
8    onSuccess: () => {
9      queryClient.invalidateQueries({ queryKey: ['posts'] });
10    },
11  });
12
13  return (
14    <button onClick={() => mutation.mutate({ title: 'New Post' })}>
15      Create Post
16    </button>
17  );
18}

Infinite Queries

For paginated data:

jsx
1import { useInfiniteQuery } from '@tanstack/react-query';
2
3function InfinitePosts() {
4  const {
5    data,
6    fetchNextPage,
7    hasNextPage,
8    isFetchingNextPage,
9  } = useInfiniteQuery({
10    queryKey: ['posts'],
11    queryFn: ({ pageParam = 0 }) => fetchPosts(pageParam),
12    getNextPageParam: (lastPage, pages) => lastPage.nextCursor,
13  });
14
15  return (
16    <div>
17      {data?.pages.map((page, i) => (
18        <div key={i}>
19          {page.posts.map(post => (
20            <div key={post.id}>{post.title}</div>
21          ))}
22        </div>
23      ))}
24      <button
25        onClick={() => fetchNextPage()}
26        disabled={!hasNextPage || isFetchingNextPage}
27      >
28        {isFetchingNextPage ? 'Loading...' : 'Load More'}
29      </button>
30    </div>
31  );
32}

Why You Should Use React Query

1. Reduces Boilerplate: No need to write loading states, error handling, and caching logic manually.
2. Better User Experience: Automatic background updates keep your data fresh.
3. Performance: Intelligent caching reduces unnecessary network requests.
4. Developer Experience: Excellent DevTools for debugging and monitoring.
5. Flexibility: Works with any data fetching library or API.

React Query has become an essential tool in the React ecosystem, and for good reason. It solves many common problems developers face when working with server state, making applications more performant and user-friendly.

For more details, refer to the official React Query documentation.