State Management with React Query + Zustand

Version 1.1.0 | TanStack Query v5 | Zustand v5 | March 2026

Note: This document provides comprehensive patterns for AI agents and LLMs working with TanStack Query v5 and Zustand v5. All examples are verified against v5 APIs. Optimized for automated refactoring, code generation, and state management best practices.

v5 Breaking Changes (Quick Reference)

TanStack Query v5:

cacheTime → gcTime
keepPreviousData option → placeholderData: keepPreviousData (imported helper)
isPreviousData → isPlaceholderData
onSuccess/onError/onSettled removed from useQuery — still valid on useMutation
suspense: true on useQuery removed → use useSuspenseQuery

Zustand v5:

shallow as 2nd arg removed → useShallow from zustand/shallow
Selectors returning new references need useShallow to avoid infinite loops

Security: Persist Middleware

Never persist auth tokens, passwords, or secrets to localStorage/sessionStorage. Use partialize to persist only non-sensitive state. Manage tokens via HttpOnly cookies.

Comprehensive patterns for server state (React Query) and client state (Zustand). Contains 26+ rules for efficient data fetching and state management.

When to Apply

Reference these guidelines when:

Fetching data from APIs
Managing server state and caching
Handling mutations and optimistic updates
Creating client-side stores
Combining React Query with Zustand

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	React Query Basics	CRITICAL	`rq-`
2	Zustand Store Patterns	CRITICAL	`zs-`
3	Caching & Invalidation	HIGH	`cache-`
4	Mutations & Updates	HIGH	`mut-`
5	Optimistic Updates	MEDIUM	`opt-`
6	DevTools & Debugging	MEDIUM	`dev-`
7	Advanced Patterns	LOW	`adv-`

Quick Reference

1. React Query Basics (CRITICAL)

rq-setup - QueryClient and Provider setup
rq-usequery - Basic useQuery patterns
rq-querykeys - Query key organization
rq-loading-error - Handle loading and error states
rq-enabled - Conditional queries

2. Zustand Store Patterns (CRITICAL)

zs-create-store - Create basic store
zs-typescript - TypeScript store patterns
zs-selectors - Efficient selectors
zs-actions - Action patterns
zs-persist - Persist state to storage

3. Caching & Invalidation (HIGH)

cache-stale-time - Configure stale time
cache-gc-time - Configure garbage collection
cache-invalidation - Invalidate queries
cache-prefetch - Prefetch data
cache-initial-data - Set initial data

4. Mutations & Updates (HIGH)

mut-usemutation - Basic useMutation
mut-callbacks - onSuccess, onError callbacks
mut-invalidate - Invalidate after mutation
mut-update-cache - Direct cache updates

5. Optimistic Updates (MEDIUM)

opt-basic - Basic optimistic updates
opt-rollback - Rollback on error
opt-variables - Use mutation variables

6. DevTools & Debugging (MEDIUM)

dev-react-query - React Query DevTools
dev-zustand - Zustand DevTools
dev-debugging - Debug strategies

7. Advanced Patterns (LOW)

adv-infinite-queries - Infinite scrolling
adv-parallel-queries - Parallel requests
adv-dependent-queries - Dependent queries
adv-query-zustand - Combine RQ with Zustand

React Query Patterns

Setup

// lib/queryClient.ts
import { QueryClient } from '@tanstack/react-query'

export const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      staleTime: 1000 * 60 * 5, // 5 minutes
      gcTime: 1000 * 60 * 30,   // 30 minutes (formerly cacheTime)
      retry: 1,
      refetchOnWindowFocus: false,
    },
  },
})

// App.tsx
import { QueryClientProvider } from '@tanstack/react-query'
import { ReactQueryDevtools } from '@tanstack/react-query-devtools'
import { queryClient } from './lib/queryClient'

function App() {
  return (
    <QueryClientProvider client={queryClient}>
      <Router />
      <ReactQueryDevtools initialIsOpen={false} />
    </QueryClientProvider>
  )
}

Query Keys Factory

// lib/queryKeys.ts
export const queryKeys = {
  // All posts
  posts: {
    all: ['posts'] as const,
    lists: () => [...queryKeys.posts.all, 'list'] as const,
    list: (filters: PostFilters) =>
      [...queryKeys.posts.lists(), filters] as const,
    details: () => [...queryKeys.posts.all, 'detail'] as const,
    detail: (id: number) => [...queryKeys.posts.details(), id] as const,
  },

  // All users
  users: {
    all: ['users'] as const,
    detail: (id: number) => [...queryKeys.users.all, id] as const,
    posts: (userId: number) => [...queryKeys.users.all, userId, 'posts'] as const,
  },
}

useQuery Hook

// hooks/usePosts.ts
import { useQuery } from '@tanstack/react-query'
import { queryKeys } from '@/lib/queryKeys'
import { fetchPosts, fetchPost } from '@/api/posts'

export function usePosts(filters?: PostFilters) {
  return useQuery({
    queryKey: queryKeys.posts.list(filters ?? {}),
    queryFn: () => fetchPosts(filters),
  })
}

export function usePost(id: number) {
  return useQuery({
    queryKey: queryKeys.posts.detail(id),
    queryFn: () => fetchPost(id),
    enabled: !!id, // Only run if id exists
  })
}

// Usage in component
function PostList() {
  const { data: posts, isLoading, error } = usePosts()

  if (isLoading) return <Spinner />
  if (error) return <Error message={error.message} />

  return (
    <ul>
      {posts?.map((post) => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  )
}

useMutation Hook

// hooks/useCreatePost.ts
import { useMutation, useQueryClient } from '@tanstack/react-query'
import { queryKeys } from '@/lib/queryKeys'
import { createPost } from '@/api/posts'

export function useCreatePost() {
  const queryClient = useQueryClient()

  return useMutation({
    mutationFn: createPost,
    onSuccess: (newPost) => {
      // Invalidate and refetch posts list
      queryClient.invalidateQueries({
        queryKey: queryKeys.posts.lists(),
      })
    },
    onError: (error) => {
      console.error('Failed to create post:', error)
    },
  })
}

// Usage
function CreatePostForm() {
  const { mutate, isPending } = useCreatePost()

  const handleSubmit = (data: CreatePostData) => {
    mutate(data)
  }

  return (
    <form onSubmit={handleSubmit}>
      {/* form fields */}
      <button disabled={isPending}>
        {isPending ? 'Creating...' : 'Create'}
      </button>
    </form>
  )
}

Optimistic Updates

export function useUpdatePost() {
  const queryClient = useQueryClient()

  return useMutation({
    mutationFn: updatePost,
    onMutate: async (updatedPost) => {
      // Cancel outgoing refetches
      await queryClient.cancelQueries({
        queryKey: queryKeys.posts.detail(updatedPost.id),
      })

      // Snapshot previous value
      const previousPost = queryClient.getQueryData(
        queryKeys.posts.detail(updatedPost.id)
      )

      // Optimistically update
      queryClient.setQueryData(
        queryKeys.posts.detail(updatedPost.id),
        updatedPost
      )

      return { previousPost }
    },
    onError: (err, updatedPost, context) => {
      // Rollback on error
      queryClient.setQueryData(
        queryKeys.posts.detail(updatedPost.id),
        context?.previousPost
      )
    },
    onSettled: (data, error, variables) => {
      // Refetch after settle
      queryClient.invalidateQueries({
        queryKey: queryKeys.posts.detail(variables.id),
      })
    },
  })
}

Zustand Patterns

Basic Store

// stores/useCounterStore.ts
import { create } from 'zustand'

interface CounterState {
  count: number
  increment: () => void
  decrement: () => void
  reset: () => void
}

export const useCounterStore = create<CounterState>((set) => ({
  count: 0,
  increment: () => set((state) => ({ count: state.count + 1 })),
  decrement: () => set((state) => ({ count: state.count - 1 })),
  reset: () => set({ count: 0 }),
}))

// Usage
function Counter() {
  const { count, increment, decrement } = useCounterStore()

  return (
    <div>
      <span>{count}</span>
      <button onClick={increment}>+</button>
      <button onClick={decrement}>-</button>
    </div>
  )
}

Store with TypeScript and Middleware

// stores/useAuthStore.ts
import { create } from 'zustand'
import { persist, devtools } from 'zustand/middleware'

interface User {
  id: number
  name: string
  email: string
}

interface AuthState {
  user: User | null
  isAuthenticated: boolean
  login: (user: User) => void
  logout: () => void
}

// ✅ Never persist tokens to localStorage — use HttpOnly cookies server-side
export const useAuthStore = create<AuthState>()(
  devtools(
    persist(
      (set) => ({
        user: null,
        isAuthenticated: false,

        login: (user) =>
          set({
            user,
            isAuthenticated: true,
          }),

        logout: () =>
          set({
            user: null,
            isAuthenticated: false,
          }),
      }),
      {
        name: 'auth-storage',
        // Only persist display info and auth flag — tokens must NOT be included
        partialize: (state) => ({
          user: state.user,
          isAuthenticated: state.isAuthenticated,
        }),
      }
    )
  )
)

Selectors for Performance

// Use selectors to prevent unnecessary re-renders
function UserName() {
  // Only re-renders when user.name changes
  const name = useAuthStore((state) => state.user?.name)
  return <span>{name}</span>
}

// Multiple selectors
function UserInfo() {
  const user = useAuthStore((state) => state.user)
  const isAuthenticated = useAuthStore((state) => state.isAuthenticated)

  if (!isAuthenticated) return <LoginButton />
  return <span>{user?.name}</span>
}

Combining React Query + Zustand

// Server state: React Query (what comes from API)
const { data: posts } = usePosts()

// Client state: Zustand (UI state)
const { selectedPostId, selectPost } = useUIStore()

// Use together
const selectedPost = posts?.find((p) => p.id === selectedPostId)

How to Use

Read individual rule files for detailed explanations and code examples:

rules/rq-usequery.md
rules/rq-query-keys.md
rules/rq-mutation-setup.md
rules/rq-optimistic-updates.md
rules/zs-create-store.md
rules/zs-persist.md
rules/rq-query-invalidation.md
rules/rq-prefetching.md

References

React Query (TanStack Query)

Zustand

License

This skill is provided as-is for educational and development purposes. React Query is MIT licensed by TanStack. Zustand is MIT licensed by Poimandres (pmnd.rs).

state-management