Top 5 Features of React Query Every Developer Should Know

React Query has revolutionized how we handle server state management in React applications. As someone who’s worked extensively with this powerful library, I want to share the game-changing features that have made it an essential tool in my development toolkit.

1. Automatic Background Data Refetching

One of the most impressive features of React Query is its intelligent automatic background refetching. Remember those days when we had to manually implement refresh logic? Those days are gone.

const { data, isLoading } = useQuery({
  queryKey: ['todos'],
  queryFn: fetchTodos,
  refetchInterval: 1000 * 60, // Refetch every minute
  staleTime: 1000 * 30 // Consider data stale after 30 seconds
})

2. Built-in Cache Management

The built-in caching mechanism is truly a masterpiece. It automatically caches your API responses and manages that cache intelligently, giving you optimal performance without any extra configuration.

const useTodoQuery = (todoId) => {
  return useQuery({
    queryKey: ['todo', todoId],
    queryFn: () => fetchTodoById(todoId),
    cacheTime: 1000 * 60 * 10 // Cache persists for 10 minutes
  })
}

3. Parallel Queries

Need to fetch multiple resources simultaneously? React Query makes it incredibly simple with parallel queries. No more promise.all chains!

const { data: [users, posts, comments] } = useQueries({
  queries: [
    { queryKey: ['users'], queryFn: fetchUsers },
    { queryKey: ['posts'], queryFn: fetchPosts },
    { queryKey: ['comments'], queryFn: fetchComments }
  ]
})

4. Optimistic Updates

The optimistic updates feature is like having a crystal ball for your UI. It lets you update the interface immediately while the server request is still processing, creating a smooth, instant-feel user experience.

const mutation = useMutation({
  mutationFn: updateTodo,
  onMutate: async (newTodo) => {
    await queryClient.cancelQueries(['todos'])
    const previousTodos = queryClient.getQueryData(['todos'])
    queryClient.setQueryData(['todos'], old => [...old, newTodo])
    return { previousTodos }
  },
  onError: (err, newTodo, context) => {
    queryClient.setQueryData(['todos'], context.previousTodos)
  }
})

5. Infinite Queries

Implementation of infinite scrolling has never been easier. React Query’s infinite queries feature handles all the complexity of pagination and data merging for you.

const {
  data,
  fetchNextPage,
  hasNextPage
} = useInfiniteQuery({
  queryKey: ['projects'],
  queryFn: fetchProjectPage,
  getNextPageParam: (lastPage) => lastPage.nextCursor
})

These features are just the tip of the iceberg, but they’ve fundamentally changed how I approach data fetching in React applications. By leveraging these capabilities, you can build more robust, performant, and user-friendly applications with less code and fewer headaches.