A small, fast and scalable bearbones state-management solution using simplified flux principles. Has a comfy API based on hooks, isn't boilerplatey or opinionated.

Don't disregard it because it's cute. It has quite the claws, lots of time was spent dealing with common pitfalls, like the dreaded zombie child problem, react concurrency, and context loss between mixed renderers. It may be the one state-manager in the React space that gets all of these right.

You can try a live demo here.

1npm install zustand

:warning: This readme is written for JavaScript users. If you are a TypeScript user, be sure to check out our TypeScript Usage section.

First create a store

Your store is a hook! You can put anything in it: primitives, objects, functions. State has to be updated immutably and the set function merges state to help it.

1import { create } from 'zustand'
2
3const useBearStore = create((set) => ({
4  bears: 0,
5  increasePopulation: () => set((state) => ({ bears: state.bears + 1 })),
6  removeAllBears: () => set({ bears: 0 }),
7}))

Then bind your components, and that's it!

Use the hook anywhere, no providers are needed. Select your state and the component will re-render on changes.

1function BearCounter() {
2  const bears = useBearStore((state) => state.bears)
3  return <h1>{bears} around here ...</h1>
4}
5
6function Controls() {
7  const increasePopulation = useBearStore((state) => state.increasePopulation)
8  return <button onClick={increasePopulation}>one up</button>
9}

Why zustand over redux?

• Simple and un-opinionated
• Makes hooks the primary means of consuming state
• Doesn't wrap your app in context providers
• Can inform components transiently (without causing render)

Why zustand over context?

• Less boilerplate
• Renders components only on changes
• Centralized, action-based state management

---

Recipes

Fetching everything

You can, but bear in mind that it will cause the component to update on every state change!

1const state = useBearStore()

Selecting multiple state slices

It detects changes with strict-equality (old === new) by default, this is efficient for atomic state picks.

1const nuts = useBearStore((state) => state.nuts)
2const honey = useBearStore((state) => state.honey)

If you want to construct a single object with multiple state-picks inside, similar to redux's mapStateToProps, you can use useShallow to prevent unnecessary rerenders when the selector output does not change according to shallow equal.

1import { create } from 'zustand'
2import { useShallow } from 'zustand/react/shallow'
3
4const useBearStore = create((set) => ({
5  nuts: 0,
6  honey: 0,
7  treats: {},
8  // ...
9}))
10
11// Object pick, re-renders the component when either state.nuts or state.honey change
12const { nuts, honey } = useBearStore(
13  useShallow((state) => ({ nuts: state.nuts, honey: state.honey })),
14)
15
16// Array pick, re-renders the component when either state.nuts or state.honey change
17const [nuts, honey] = useBearStore(
18  useShallow((state) => [state.nuts, state.honey]),
19)
20
21// Mapped picks, re-renders the component when state.treats changes in order, count or keys
22const treats = useBearStore(useShallow((state) => Object.keys(state.treats)))

For more control over re-rendering, you may provide any custom equality function (this example requires the use of createWithEqualityFn).

1const treats = useBearStore(
2  (state) => state.treats,
3  (oldTreats, newTreats) => compare(oldTreats, newTreats),
4)

Overwriting state

The set function has a second argument, false by default. Instead of merging, it will replace the state model. Be careful not to wipe out parts you rely on, like actions.

1import omit from 'lodash-es/omit'
2
3const useFishStore = create((set) => ({
4  salmon: 1,
5  tuna: 2,
6  deleteEverything: () => set({}, true), // clears the entire store, actions included
7  deleteTuna: () => set((state) => omit(state, ['tuna']), true),
8}))

Async actions

Just call set when you're ready, zustand doesn't care if your actions are async or not.

1const useFishStore = create((set) => ({
2  fishies: {},
3  fetch: async (pond) => {
4    const response = await fetch(pond)
5    set({ fishies: await response.json() })
6  },
7}))

Read from state in actions

set allows fn-updates set(state => result), but you still have access to state outside of it through get.

1const useSoundStore = create((set, get) => ({
2  sound: 'grunt',
3  action: () => {
4    const sound = get().sound
5    ...

Reading/writing state and reacting to changes outside of components

Sometimes you need to access state in a non-reactive way or act upon the store. For these cases, the resulting hook has utility functions attached to its prototype.

:warning: This technique is not recommended for adding state in React Server Components (typically in Next.js 13 and above). It can lead to unexpected bugs and privacy issues for your users. For more details, see #2200.

1const useDogStore = create(() => ({ paw: true, snout: true, fur: true }))
2
3// Getting non-reactive fresh state
4const paw = useDogStore.getState().paw
5// Listening to all changes, fires synchronously on every change
6const unsub1 = useDogStore.subscribe(console.log)
7// Updating state, will trigger listeners
8useDogStore.setState({ paw: false })
9// Unsubscribe listeners
10unsub1()
11
12// You can of course use the hook as you always would
13function Component() {
14  const paw = useDogStore((state) => state.paw)
15  ...

Using subscribe with selector

If you need to subscribe with a selector, subscribeWithSelector middleware will help.

With this middleware subscribe accepts an additional signature:

1subscribe(selector, callback, options?: { equalityFn, fireImmediately }): Unsubscribe

1import { subscribeWithSelector } from 'zustand/middleware'
2const useDogStore = create(
3  subscribeWithSelector(() => ({ paw: true, snout: true, fur: true })),
4)
5
6// Listening to selected changes, in this case when "paw" changes
7const unsub2 = useDogStore.subscribe((state) => state.paw, console.log)
8// Subscribe also exposes the previous value
9const unsub3 = useDogStore.subscribe(
10  (state) => state.paw,
11  (paw, previousPaw) => console.log(paw, previousPaw),
12)
13// Subscribe also supports an optional equality function
14const unsub4 = useDogStore.subscribe(
15  (state) => [state.paw, state.fur],
16  console.log,
17  { equalityFn: shallow },
18)
19// Subscribe and fire immediately
20const unsub5 = useDogStore.subscribe((state) => state.paw, console.log, {
21  fireImmediately: true,
22})

Using zustand without React

Zustand core can be imported and used without the React dependency. The only difference is that the create function does not return a hook, but the API utilities.

1import { createStore } from 'zustand/vanilla'
2
3const store = createStore((set) => ...)
4const { getState, setState, subscribe, getInitialState } = store
5
6export default store

You can use a vanilla store with useStore hook available since v4.

1import { useStore } from 'zustand'
2import { vanillaStore } from './vanillaStore'
3
4const useBoundStore = (selector) => useStore(vanillaStore, selector)

:warning: Note that middlewares that modify set or get are not applied to getState and setState.

Transient updates (for often occurring state-changes)

The subscribe function allows components to bind to a state-portion without forcing re-render on changes. Best combine it with useEffect for automatic unsubscribe on unmount. This can make a drastic performance impact when you are allowed to mutate the view directly.

1const useScratchStore = create((set) => ({ scratches: 0, ... }))
2
3const Component = () => {
4  // Fetch initial state
5  const scratchRef = useRef(useScratchStore.getState().scratches)
6  // Connect to the store on mount, disconnect on unmount, catch state-changes in a reference
7  useEffect(() => useScratchStore.subscribe(
8    state => (scratchRef.current = state.scratches)
9  ), [])
10  ...

Sick of reducers and changing nested states? Use Immer!

Reducing nested structures is tiresome. Have you tried immer?

1import { produce } from 'immer'
2
3const useLushStore = create((set) => ({
4  lush: { forest: { contains: { a: 'bear' } } },
5  clearForest: () =>
6    set(
7      produce((state) => {
8        state.lush.forest.contains = null
9      }),
10    ),
11}))
12
13const clearForest = useLushStore((state) => state.clearForest)
14clearForest()

Alternatively, there are some other solutions.

Persist middleware

You can persist your store's data using any kind of storage.

1import { create } from 'zustand'
2import { persist, createJSONStorage } from 'zustand/middleware'
3
4const useFishStore = create(
5  persist(
6    (set, get) => ({
7      fishes: 0,
8      addAFish: () => set({ fishes: get().fishes + 1 }),
9    }),
10    {
11      name: 'food-storage', // name of the item in the storage (must be unique)
12      storage: createJSONStorage(() => sessionStorage), // (optional) by default, 'localStorage' is used
13    },
14  ),
15)

See the full documentation for this middleware.

Immer middleware

Immer is available as middleware too.

1import { create } from 'zustand'
2import { immer } from 'zustand/middleware/immer'
3
4const useBeeStore = create(
5  immer((set) => ({
6    bees: 0,
7    addBees: (by) =>
8      set((state) => {
9        state.bees += by
10      }),
11  })),
12)

Can't live without redux-like reducers and action types?

1const types = { increase: 'INCREASE', decrease: 'DECREASE' }
2
3const reducer = (state, { type, by = 1 }) => {
4  switch (type) {
5    case types.increase:
6      return { grumpiness: state.grumpiness + by }
7    case types.decrease:
8      return { grumpiness: state.grumpiness - by }
9  }
10}
11
12const useGrumpyStore = create((set) => ({
13  grumpiness: 0,
14  dispatch: (args) => set((state) => reducer(state, args)),
15}))
16
17const dispatch = useGrumpyStore((state) => state.dispatch)
18dispatch({ type: types.increase, by: 2 })

Or, just use our redux-middleware. It wires up your main-reducer, sets the initial state, and adds a dispatch function to the state itself and the vanilla API.

1import { redux } from 'zustand/middleware'
2
3const useGrumpyStore = create(redux(reducer, initialState))

Redux devtools

Install the Redux DevTools Chrome extension to use the devtools middleware.

1import { devtools } from 'zustand/middleware'
2
3// Usage with a plain action store, it will log actions as "setState"
4const usePlainStore = create(devtools((set) => ...))
5// Usage with a redux store, it will log full action types
6const useReduxStore = create(devtools(redux(reducer, initialState)))

One redux devtools connection for multiple stores

1import { devtools } from 'zustand/middleware'
2
3// Usage with a plain action store, it will log actions as "setState"
4const usePlainStore1 = create(devtools((set) => ..., { name, store: storeName1 }))
5const usePlainStore2 = create(devtools((set) => ..., { name, store: storeName2 }))
6// Usage with a redux store, it will log full action types
7const useReduxStore1 = create(devtools(redux(reducer, initialState)), { name, store: storeName3 })
8const useReduxStore2 = create(devtools(redux(reducer, initialState)), { name, store: storeName4 })

Assigning different connection names will separate stores in redux devtools. This also helps group different stores into separate redux devtools connections.

devtools takes the store function as its first argument, optionally you can name the store or configure serialize options with a second argument.

Name store: devtools(..., {name: "MyStore"}), which will create a separate instance named "MyStore" in the devtools.

Serialize options: devtools(..., { serialize: { options: true } }).

Logging Actions

devtools will only log actions from each separated store unlike in a typical combined reducers redux store. See an approach to combining stores https://github.com/pmndrs/zustand/issues/163

You can log a specific action type for each set function by passing a third parameter:

1const useBearStore = create(devtools((set) => ({
2  ...
3  eatFish: () => set(
4    (prev) => ({ fishes: prev.fishes > 1 ? prev.fishes - 1 : 0 }),
5    undefined,
6    'bear/eatFish'
7  ),
8  ...

You can also log the action's type along with its payload:

1  ...
2  addFishes: (count) => set(
3    (prev) => ({ fishes: prev.fishes + count }),
4    undefined,
5    { type: 'bear/addFishes', count, }
6  ),
7  ...

If an action type is not provided, it is defaulted to "anonymous". You can customize this default value by providing an anonymousActionType parameter:

1devtools(..., { anonymousActionType: 'unknown', ... })

If you wish to disable devtools (on production for instance). You can customize this setting by providing the enabled parameter:

1devtools(..., { enabled: false, ... })

React context

The store created with create doesn't require context providers. In some cases, you may want to use contexts for dependency injection or if you want to initialize your store with props from a component. Because the normal store is a hook, passing it as a normal context value may violate the rules of hooks.

The recommended method available since v4 is to use the vanilla store.

1import { createContext, useContext } from 'react'
2import { createStore, useStore } from 'zustand'
3
4const store = createStore(...) // vanilla store without hooks
5
6const StoreContext = createContext()
7
8const App = () => (
9  <StoreContext.Provider value={store}>
10    ...
11  </StoreContext.Provider>
12)
13
14const Component = () => {
15  const store = useContext(StoreContext)
16  const slice = useStore(store, selector)
17  ...

TypeScript Usage

Basic typescript usage doesn't require anything special except for writing create<State>()(...) instead of create(...)...

1import { create } from 'zustand'
2import { devtools, persist } from 'zustand/middleware'
3import type {} from '@redux-devtools/extension' // required for devtools typing
4
5interface BearState {
6  bears: number
7  increase: (by: number) => void
8}
9
10const useBearStore = create<BearState>()(
11  devtools(
12    persist(
13      (set) => ({
14        bears: 0,
15        increase: (by) => set((state) => ({ bears: state.bears + by })),
16      }),
17      {
18        name: 'bear-storage',
19      },
20    ),
21  ),
22)

A more complete TypeScript guide is here.

Best practices

• You may wonder how to organize your code for better maintenance: Splitting the store into separate slices.
• Recommended usage for this unopinionated library: Flux inspired practice.
• Calling actions outside a React event handler in pre-React 18.
• Testing
• For more, have a look in the docs folder

Third-Party Libraries

Some users may want to extend Zustand's feature set which can be done using third-party libraries made by the community. For information regarding third-party libraries with Zustand, visit the doc.

Comparison with other libraries

• Difference between zustand and other state management libraries for React