Persisting Zustand State with AsyncStorage
Wrap a Zustand store with the persist middleware backed by AsyncStorage so state survives app restarts, and handle rehydration timing.
Persisting Zustand State with AsyncStorage is a free React Native Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the React Native Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Why Persist State?
By default, Zustand state lives only in memory and is lost when the app closes. Persisting state means saving it to the device's local storage so it survives app restarts. This is essential for user preferences, authentication tokens, shopping carts, or any data the user expects to still be there when they reopen the app.
Installing AsyncStorage
AsyncStorage is the standard key-value storage API for React Native. In Expo managed workflow, install the community package @react-native-async-storage/async-storage. Zustand's built-in persist middleware works with any storage adapter, and AsyncStorage is the most common choice for mobile apps.
npx expo install @react-native-async-storage/async-storageAdding the persist Middleware
Wrap the store creator with persist imported from zustand/middleware. Pass it your store factory and a configuration object with a name key (the AsyncStorage key where state will be saved) and a storage key (pointing to your AsyncStorage adapter). Zustand handles reading and writing automatically.
import { create } from 'zustand';
import { persist, createJSONStorage } from 'zustand/middleware';
import AsyncStorage from '@react-native-async-storage/async-storage';
export const useSettingsStore = create(
persist<SettingsStore>(
(set) => ({
theme: 'light',
notifications: true,
setTheme: (theme) => set({ theme }),
toggleNotifications: () =>
set((state) => ({ notifications: !state.notifications })),
}),
{
name: 'settings-store',
storage: createJSONStorage(() => AsyncStorage),
}
)
);How Persist Works Internally
When the store is first created, persist reads from AsyncStorage and rehydrates (restores) any previously saved state before rendering the first component. When state changes via set, persist automatically serializes the state to JSON and writes it to AsyncStorage asynchronously. This all happens without any extra code in your components.
Handling the Rehydration Delay
AsyncStorage reads are asynchronous, so on the first render the store may still contain the initial state before rehydration finishes. Zustand's persist middleware adds a _hasHydrated flag and an onFinishHydration callback. Use these to show a loading screen while persisted state is loading from disk.
const hasHydrated = useSettingsStore((state) => state._hasHydrated);
if (!hasHydrated) {
return <ActivityIndicator />; // Show loading until store is ready
}
// Alternatively, listen to hydration completion:
useEffect(() => {
const unsub = useSettingsStore.persist.onFinishHydration(() => {
setReady(true);
});
return unsub;
}, []);Persisting Only Part of the State
You often do not want to persist everything in the store — for example, transient loading states or error messages should not be saved. Use the partialize option to select which fields to persist. The returned object contains only the keys you want to write to AsyncStorage.
persist<AuthStore>(
(set) => ({
user: null,
token: null,
isLoading: false, // transient — don't persist
error: null, // transient — don't persist
login: (user, token) => set({ user, token }),
logout: () => set({ user: null, token: null }),
}),
{
name: 'auth-store',
storage: createJSONStorage(() => AsyncStorage),
partialize: (state) => ({ user: state.user, token: state.token }),
}
)Versioning and Migration
When you change the structure of your persisted state in a new app release, old data on users' devices may not match the new shape. Use the version and migrate options to upgrade stored state from one version to the next. Increment version with each structural change and handle old state in the migrate function.
persist<SettingsStore>(
(set) => ({ /* ... */ }),
{
name: 'settings-store',
storage: createJSONStorage(() => AsyncStorage),
version: 2,
migrate: (persistedState: any, version: number) => {
if (version === 1) {
// Rename darkMode to theme in version 2
persistedState.theme = persistedState.darkMode ? 'dark' : 'light';
delete persistedState.darkMode;
}
return persistedState;
},
}
)Clearing Persisted State
To clear the persisted state — for example when the user logs out — call useStore.persist.clearStorage(). This removes the data from AsyncStorage. You can also call useStore.getState().reset() to clear the in-memory state at the same time. Doing both ensures the user starts fresh on the next app launch.
async function handleLogout() {
// Clear in-memory state
useAuthStore.getState().logout();
// Clear persisted state from AsyncStorage
await useAuthStore.persist.clearStorage();
navigation.reset({ index: 0, routes: [{ name: 'Login' }] });
}Using SecureStore for Sensitive Data
For sensitive values like auth tokens, prefer Expo SecureStore over plain AsyncStorage. SecureStore uses the device's secure enclave (iOS Keychain / Android Keystore) to encrypt data at rest. You can create a custom Zustand storage adapter using SecureStore's getItemAsync and setItemAsync methods.
import * as SecureStore from 'expo-secure-store';
const secureStorage = {
getItem: async (name: string) => await SecureStore.getItemAsync(name),
setItem: async (name: string, value: string) =>
await SecureStore.setItemAsync(name, value),
removeItem: async (name: string) =>
await SecureStore.deleteItemAsync(name),
};
// Use secureStorage instead of AsyncStorage:
storage: createJSONStorage(() => secureStorage),Debugging Persisted State
To inspect what is stored in AsyncStorage during development, call AsyncStorage.getAllKeys() and AsyncStorage.multiGet(keys) in the dev console or a debug screen. You can also manually clear stale persisted state with AsyncStorage.clear() when testing migration logic. Always test with a fresh install to simulate real user upgrade scenarios.
// Debug helper — call from a dev-only screen
async function printStorage() {
const keys = await AsyncStorage.getAllKeys();
const pairs = await AsyncStorage.multiGet(keys);
pairs.forEach(([key, value]) => {
console.log(key, ':', JSON.parse(value ?? 'null'));
});
}Persisting a Cart Store Example
Here is a realistic cart store that persists its items list across app restarts. Loading and error state are excluded from persistence using partialize. The total is derived on the fly in the component rather than stored, so it is always consistent with the items array after rehydration.
export const useCartStore = create(
persist<CartStore>(
(set, get) => ({
items: [],
addItem: (item) => set((state) => ({ items: [...state.items, item] })),
removeItem: (id) =>
set((state) => ({ items: state.items.filter((i) => i.id !== id) })),
clearCart: () => set({ items: [] }),
}),
{
name: 'cart-store',
storage: createJSONStorage(() => AsyncStorage),
partialize: (state) => ({ items: state.items }),
}
)
);Quick Check
Test your understanding of React Native Mobile Development concepts from this lesson.
Lesson Recap
In this lesson you learned: the persist middleware wraps a Zustand store to save and restore state from AsyncStorage automatically, partialize controls which fields are persisted to avoid saving transient loading or error state, and version with migrate handles breaking state shape changes across app updates. Next up we explore the slices pattern and Devtools integration in Zustand.
Frequently asked questions
Is the “Persisting Zustand State with AsyncStorage” lesson free?
Yes — the full text of “Persisting Zustand State with AsyncStorage” is free to read here on the web, and the React Native Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the React Native Academy course, upgrade to CoddyKit PRO.
What will I learn in “Persisting Zustand State with AsyncStorage”?
Wrap a Zustand store with the persist middleware backed by AsyncStorage so state survives app restarts, and handle rehydration timing. You practise React Native Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start React Native Academy?
No prior experience is required. React Native Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Persisting Zustand State with AsyncStorage” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this React Native Academy lesson?
Yes. Every React Native Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Creating a Zustand Store
- Reading and Updating Store State in Components
- Persisting Zustand State with AsyncStorage
- Slices Pattern and Devtools Integration