jvegaf/zustand-state-management

Zustand State Management

Last Updated: 2026-01-21 Latest Version: [email protected] (released 2026-01-12) Dependencies: React 18-19, TypeScript 5+

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Quick Start

npm install zustand

TypeScript Store (CRITICAL: use create<T>()() double parentheses):

import { create } from 'zustand';

interface BearStore {
  bears: number;
  increase: (by: number) => void;
}

const useBearStore = create<BearStore>()(set => ({
  bears: 0,
  increase: by => set(state => ({ bears: state.bears + by })),
}));

Use in Components:

const bears = useBearStore(state => state.bears); // Only re-renders when bears changes
const increase = useBearStore(state => state.increase);

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Core Patterns

Basic Store (JavaScript):

const useStore = create(set => ({
  count: 0,
  increment: () => set(state => ({ count: state.count + 1 })),
}));

TypeScript Store (Recommended):

interface CounterStore {
  count: number;
  increment: () => void;
}
const useStore = create<CounterStore>()(set => ({
  count: 0,
  increment: () => set(state => ({ count: state.count + 1 })),
}));

Persistent Store (survives page reloads):

import { persist, createJSONStorage } from 'zustand/middleware';

const useStore = create<UserPreferences>()(
  persist(set => ({ theme: 'system', setTheme: theme => set({ theme }) }), {
    name: 'user-preferences',
    storage: createJSONStorage(() => localStorage),
  }),
);

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Critical Rules

Always Do

✅ Use create<T>()() (double parentheses) in TypeScript for middleware compatibility ✅ Define separate interfaces for state and actions ✅ Use selector functions to extract specific state slices ✅ Use set with updater functions for derived state: set((state) => ({ count: state.count + 1 })) ✅ Use unique names for persist middleware storage keys ✅ Handle Next.js hydration with hasHydrated flag pattern ✅ Use useShallow hook for selecting multiple values ✅ Keep actions pure (no side effects except state updates)

Never Do

❌ Use create<T>(...) (single parentheses) in TypeScript - breaks middleware types ❌ Mutate state directly: set((state) => { state.count++; return state }) - use immutable updates ❌ Create new objects in selectors: useStore((state) => ({ a: state.a })) - causes infinite renders ❌ Use same storage name for multiple stores - causes data collisions ❌ Access localStorage during SSR without hydration check ❌ Use Zustand for server state - use TanStack Query instead ❌ Export store instance directly - always export the hook

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Known Issues Prevention

This skill prevents 6 documented issues:

Issue #1: Next.js Hydration Mismatch

Error: "Text content does not match server-rendered HTML" or "Hydration failed"

Source:

• DEV Community: Persist middleware in Next.js
• GitHub Discussions #2839

Why It Happens: Persist middleware reads from localStorage on client but not on server, causing state mismatch.

Prevention:

import { create } from 'zustand'
import { persist } from 'zustand/middleware'

interface StoreWithHydration {
  count: number
  _hasHydrated: boolean
  setHasHydrated: (hydrated: boolean) => void
  increase: () => void
}

const useStore = create<StoreWithHydration>()(
  persist(
    (set) => ({
      count: 0,
      _hasHydrated: false,
      setHasHydrated: (hydrated) => set({ _hasHydrated: hydrated }),
      increase: () => set((state) => ({ count: state.count + 1 })),
    }),
    {
      name: 'my-store',
      onRehydrateStorage: () => (state) => {
        state?.setHasHydrated(true)
      },
    },
  ),
)

// In component
function MyComponent() {
  const hasHydrated = useStore((state) => state._hasHydrated)

  if (!hasHydrated) {
    return <div>Loading...</div>
  }

  // Now safe to render with persisted state
  return <ActualContent />
}

Issue #2: TypeScript Double Parentheses Missing

Error: Type inference fails, StateCreator types break with middleware

Source: Official Zustand TypeScript Guide

Why It Happens: The currying syntax create<T>()() is required for middleware to work with TypeScript inference.

Prevention:

// ❌ WRONG - Single parentheses
const useStore = create<MyStore>(set => ({
  // ...
}));

// ✅ CORRECT - Double parentheses
const useStore = create<MyStore>()(set => ({
  // ...
}));

Rule: Always use create<T>()() in TypeScript, even without middleware (future-proof).

Issue #3: Persist Middleware Import Error

Error: "Attempted import error: 'createJSONStorage' is not exported from 'zustand/middleware'"

Source: GitHub Discussion #2839

Why It Happens: Wrong import path or version mismatch between zustand and build tools.

Prevention:

// ✅ CORRECT imports for v5
import { create } from 'zustand';
import { persist, createJSONStorage } from 'zustand/middleware';

// Verify versions
// [email protected] includes createJSONStorage
// [email protected] uses different API

// Check your package.json
// "zustand": "^5.0.9"

Issue #4: Infinite Render Loop

Error: Component re-renders infinitely, browser freezes

Uncaught Error: Maximum update depth exceeded. This can happen when a component repeatedly calls setState inside componentWillUpdate or componentDidUpdate.

Source:

• GitHub Discussions #2642
• Issue #2863

Why It Happens: Creating new object references in selectors causes Zustand to think state changed.

v5 Breaking Change: Zustand v5 made this error MORE explicit compared to v4. In v4, this behavior was "non-ideal" but could go unnoticed. In v5, you'll immediately see the "Maximum update depth exceeded" error.

Prevention:

import { useShallow } from 'zustand/shallow';

// ❌ WRONG - Creates new object every time
const { bears, fishes } = useStore(state => ({
  bears: state.bears,
  fishes: state.fishes,
}));

// ✅ CORRECT Option 1 - Select primitives separately
const bears = useStore(state => state.bears);
const fishes = useStore(state => state.fishes);

// ✅ CORRECT Option 2 - Use useShallow hook for multiple values
const { bears, fishes } = useStore(useShallow(state => ({ bears: state.bears, fishes: state.fishes })));

Issue #5: Slices Pattern TypeScript Complexity

Error: StateCreator types fail to infer, complex middleware types break

Source: Official Slices Pattern Guide

Why It Happens: Combining multiple slices requires explicit type annotations for middleware compatibility.

Prevention:

import { create, StateCreator } from 'zustand';

// Define slice types
interface BearSlice {
  bears: number;
  addBear: () => void;
}

interface FishSlice {
  fishes: number;
  addFish: () => void;
}

// Create slices with proper types
const createBearSlice: StateCreator<
  BearSlice & FishSlice, // Combined store type
  [], // Middleware mutators (empty if none)
  [], // Chained middleware (empty if none)
  BearSlice // This slice's type
> = set => ({
  bears: 0,
  addBear: () => set(state => ({ bears: state.bears + 1 })),
});

const createFishSlice: StateCreator<BearSlice & FishSlice, [], [], FishSlice> = set => ({
  fishes: 0,
  addFish: () => set(state => ({ fishes: state.fishes + 1 })),
});

// Combine slices
const useStore = create<BearSlice & FishSlice>()((...a) => ({
  ...createBearSlice(...a),
  ...createFishSlice(...a),
}));

Issue #6: Persist Middleware Race Condition (Fixed v5.0.10+)

Error: Inconsistent state during concurrent rehydration attempts

Source:

• GitHub PR #3336
• Release v5.0.10

Why It Happens: In Zustand v5.0.9 and earlier, concurrent calls to rehydrate during persist middleware initialization could cause a race condition where multiple hydration attempts would interfere with each other, leading to inconsistent state.

Prevention: Upgrade to Zustand v5.0.10 or later. No code changes needed - the fix is internal to the persist middleware.

npm install zustand@latest  # Ensure v5.0.10+

Note: This was fixed in v5.0.10 (January 2026). If you're using v5.0.9 or earlier and experiencing state inconsistencies with persist middleware, upgrade immediately.

---

Middleware

Persist (localStorage):

import { persist, createJSONStorage } from 'zustand/middleware';

const useStore = create<MyStore>()(
  persist(set => ({ data: [], addItem: item => set(state => ({ data: [...state.data, item] })) }), {
    name: 'my-storage',
    partialize: state => ({ data: state.data }), // Only persist 'data'
  }),
);

Devtools (Redux DevTools):

import { devtools } from 'zustand/middleware';

const useStore = create<CounterStore>()(
  devtools(set => ({ count: 0, increment: () => set(s => ({ count: s.count + 1 }), undefined, 'increment') }), {
    name: 'CounterStore',
  }),
);

v4→v5 Migration Note: In Zustand v4, devtools was imported from 'zustand/middleware/devtools'. In v5, use 'zustand/middleware' (as shown above). If you see "Module not found: Can't resolve 'zustand/middleware/devtools'", update your import path.

Combining Middlewares (order matters):

const useStore = create<MyStore>()(
  devtools(
    persist(
      set => ({
        /* ... */
      }),
      { name: 'storage' },
    ),
    { name: 'MyStore' },
  ),
);

---

Common Patterns

Computed/Derived Values (in selector, not stored):

const count = useStore(state => state.items.length); // Computed on read

Async Actions:

const useAsyncStore = create<AsyncStore>()(set => ({
  data: null,
  isLoading: false,
  fetchData: async () => {
    set({ isLoading: true });
    const response = await fetch('/api/data');
    set({ data: await response.text(), isLoading: false });
  },
}));

Resetting Store:

const initialState = { count: 0, name: '' };
const useStore = create<ResettableStore>()(set => ({
  ...initialState,
  reset: () => set(initialState),
}));

Selector with Params:

const todo = useStore(state => state.todos.find(t => t.id === id));

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Bundled Resources

Templates: basic-store.ts, typescript-store.ts, persist-store.ts, slices-pattern.ts, devtools-store.ts, nextjs-store.ts, computed-store.ts, async-actions-store.ts

References: middleware-guide.md (persist/devtools/immer/custom), typescript-patterns.md (type inference issues), nextjs-hydration.md (SSR/hydration), migration-guide.md (from Redux/Context/v4)

Scripts: check-versions.sh (version compatibility)

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Advanced Topics

Vanilla Store (Without React):

import { createStore } from 'zustand/vanilla';

const store = createStore<CounterStore>()(set => ({ count: 0, increment: () => set(s => ({ count: s.count + 1 })) }));
const unsubscribe = store.subscribe(state => console.log(state.count));
store.getState().increment();

Custom Middleware:

const logger: Logger = (f, name) => (set, get, store) => {
  const loggedSet: typeof set = (...a) => {
    set(...a);
    console.log(`[${name}]:`, get());
  };
  return f(loggedSet, get, store);
};

Immer Middleware (Mutable Updates):

import { immer } from 'zustand/middleware/immer';

const useStore = create<TodoStore>()(
  immer(set => ({
    todos: [],
    addTodo: text =>
      set(state => {
        state.todos.push({ id: Date.now().toString(), text });
      }),
  })),
);

v5.0.3→v5.0.4 Migration Note: If upgrading from v5.0.3 to v5.0.4+ and immer middleware stops working, verify you're using the import path shown above (zustand/middleware/immer). Some users reported issues after the v5.0.4 update that were resolved by confirming the correct import.

Experimental SSR Safe Middleware (v5.0.9+):

Status: Experimental (API may change)

Zustand v5.0.9 introduced experimental unstable_ssrSafe middleware for Next.js usage. This provides an alternative approach to the _hasHydrated pattern (see Issue #1).

import { unstable_ssrSafe } from 'zustand/middleware';

const useStore = create<Store>()(
  unstable_ssrSafe(
    persist(
      set => ({
        /* state */
      }),
      { name: 'my-store' },
    ),
  ),
);

Recommendation: Continue using the _hasHydrated pattern documented in Issue #1 until this API stabilizes. Monitor Discussion #2740 for updates on when this becomes stable.

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Official Documentation

• Zustand: https://zustand.docs.pmnd.rs/
• GitHub: https://github.com/pmndrs/zustand
• TypeScript Guide: https://zustand.docs.pmnd.rs/guides/typescript
• Context7 Library ID: /pmndrs/zustand