File: beginner-typescript.md | Updated: 11/15/2025
Zustand is a lightweight state manager, particularly used with React. Zustand avoids reducers, context, and boilerplate. Paired with TypeScript, you get a strongly typed store-state, actions, and selectors-with autocomplete and compile-time safety.
In this basic guide weāll cover:
combine, devtools, persist)createWithEqualityFn (enhanced create store function)Here we describe state and actions using an Typescript interface. The <BearState> generic forces the store to match this shape.
This means if you forget a field or use the wrong type, TypeScript will complain. Unlike plain JS, this guarantees type-safe state management.
The create function uses the curried form, which results in a store of type UseBoundStore<StoreApi<BearState>>.
// store.ts
import { create } from 'zustand'
// Define types for state & actions
interface BearState {
bears: number
food: string
feed: (food: string) => void
}
// Create store using the curried form of `create`
export const useBearStore = create<BearState>()((set) => ({
bears: 2,
food: 'honey',
feed: (food) => set(() => ({ food })),
}))
Inside components, you can read state and call actions. Selectors (s) => s.bears subscribe to only what you need.
This reduces re-renders and improves performance. JS can do this too, but with TS your IDE autocompletes state fields.
import { useBearStore } from './store'
function BearCounter() {
// Select only 'bears' to avoid unnecessary re-renders
const bears = useBearStore((s) => s.bears)
return <h1>{bears} bears around</h1>
}
Resetting is useful after logout or āclear sessionā. We use typeof initialState to avoid repeating property types.
TypeScript updates automatically if initialState changes. This is safer and cleaner compared to JS.
import { create } from 'zustand'
const initialState = { bears: 0, food: 'honey' }
// Reuse state type dynamically
type BearState = typeof initialState & {
increase: (by: number) => void
reset: () => void
}
const useBearStore = create<BearState>()((set) => ({
...initialState,
increase: (by) => set((s) => ({ bears: s.bears + by })),
reset: () => set(initialState),
}))
function ResetZoo() {
const { bears, increase, reset } = useBearStore()
return (
<div>
<div>{bears}</div>
<button onClick={() => increase(5)}>Increase by 5</button>
<button onClick={reset}>Reset</button>
</div>
)
}
Zustand provides a built-in helper called ExtractState. This is useful for tests, utility functions, or component props.
It returns the full type of your storeās state and actions without having to manually redefine them. Extracting the Store type:
// store.ts
import { create, type ExtractState } from 'zustand'
export const useBearStore = create((set) => ({
bears: 3,
food: 'honey',
increase: (by: number) => set((s) => ({ bears: s.bears + by })),
}))
// Extract the type of the whole store state
export type BearState = ExtractState<typeof useBearStore>
Using extracted type in tests:
// test.cy.ts
import { BearState } from './store.ts'
test('should reset store', () => {
const snapshot: BearState = useBearStore.getState()
expect(snapshot.bears).toBeGreaterThanOrEqual(0)
})
and in utility function:
// util.ts
import { BearState } from './store.ts'
function logBearState(state: BearState) {
console.log(`We have ${state.bears} bears eating ${state.food}`)
}
logBearState(useBearStore.getState())
Sometimes you need more than one property. Returning an object from the selector lets you access multiple fields at once.
However, directly destructuring properties from that object can cause unnecessary re-renders.
To avoid this, itās recommended to wrap the selector with useShallow, which prevents re-renders when the selected values remain shallowly equal.
This is more efficient than subscribing to the whole store. TypeScript ensures you canāt accidentally misspell bears or food.
See the API documentation for more details on useShallow.
import { create } from 'zustand'
import { useShallow } from 'zustand/react/shallow'
// Bear store with explicit types
interface BearState {
bears: number
food: number
}
const useBearStore = create<BearState>()(() => ({
bears: 2,
food: 10,
}))
// In components, you can use both stores safely
function MultipleSelectors() {
const { bears, food } = useBearStore(
useShallow((state) => ({ bears: state.bears, food: state.food })),
)
return (
<div>
We have {food} units of food for {bears} bears
</div>
)
}
Not all values need to be stored directly - some can be computed from existing state. You can derive values using selectors.
This avoids duplication and keeps the store minimal. TypeScript ensures bears is a number, so math is safe.
import { create } from 'zustand'
interface BearState {
bears: number
foodPerBear: number
}
const useBearStore = create<BearState>()(() => ({
bears: 3,
foodPerBear: 2,
}))
function TotalFood() {
// Derived value: required amount food for all bears
const totalFood = useBearStore((s) => s.bears * s.foodPerBear) // don't need to have extra property `{ totalFood: 6 }` in your Store
return <div>We need ${totalFood} jars of honey</div>
}
combine middlewareThis middleware separates initial state and actions, making the code cleaner. TS automatically infers types from the state and actions, no interface needed. This is different from JS, where type safety is missing. Itās a very popular style in TypeScript projects. See the API documentation for more details.
import { create } from 'zustand'
import { combine } from 'zustand/middleware'
interface BearState {
bears: number
increase: () => void
}
// State + actions are separated
export const useBearStore = create<BearState>()(
combine({ bears: 0 }, (set) => ({
increase: () => set((s) => ({ bears: s.bears + 1 })),
})),
)
devtools middlewareThis middleware connects Zustand to Redux DevTools. You can inspect changes, time-travel, and debug state. Itās extremely useful in development. TS ensures your actions and state remain type-checked even here. See the API documentation for more details.
import { create } from 'zustand'
import { devtools } from 'zustand/middleware'
interface BearState {
bears: number
increase: () => void
}
export const useBearStore = create<BearState>()(
devtools((set) => ({
bears: 0,
increase: () => set((s) => ({ bears: s.bears + 1 })),
})),
)
persist middlewareThis middleware keeps your store in localStorage (or another storage). This means your bears survive a page refresh.
Great for apps where persistence matters. In TS, the state type stays consistent, so no runtime surprises.
See the API documentation for more details.
import { create } from 'zustand'
import { persist } from 'zustand/middleware'
interface BearState {
bears: number
increase: () => void
}
export const useBearStore = create<BearState>()(
persist(
(set) => ({
bears: 0,
increase: () => set((s) => ({ bears: s.bears + 1 })), // <-- ŃŠøŠæ ŃŠ²Š½Š¾
}),
{ name: 'bear-storage' }, // localStorage key
),
)
Actions can be async to fetch remote data. Here we fetch bears count and update state.
TS enforces correct API response type (BearData). In JS you might misspell count - TS prevents that.
import { create } from 'zustand'
interface BearData {
count: number
}
interface BearState {
bears: number
fetchBears: () => Promise<void>
}
export const useBearStore = create<BearState>()((set) => ({
bears: 0,
fetchBears: async () => {
const res = await fetch('/api/bears')
const data: BearData = await res.json()
set({ bears: data.count })
},
}))
createWithEqualityFnVariant of create with equality built-in. Useful if you always want custom equality checks.
Not common, but shows Zustandās flexibility. TS still keeps full type inference.
See the API documentation for more details.
import { createWithEqualityFn } from 'zustand/traditional'
import { shallow } from 'zustand/shallow'
const useBearStore = createWithEqualityFn(() => ({
bears: 0,
}))
const bears = useBearStore((s) => s.bears, Object.is)
// or
const bears = useBearStore((s) => ({ bears: s.bears }), shallow)
You can create more than one store for different domains. For example, BearStore manages bears and FishStore manages fish.
This keeps state isolated and easier to maintain in larger apps. With TypeScript, each store has its own strict type - you canāt accidentally mix bears and fish.
import { create } from 'zustand'
// Bear store with explicit types
interface BearState {
bears: number
addBear: () => void
}
const useBearStore = create<BearState>()((set) => ({
bears: 2,
addBear: () => set((s) => ({ bears: s.bears + 1 })),
}))
// Fish store with explicit types
interface FishState {
fish: number
addFish: () => void
}
const useFishStore = create<FishState>()((set) => ({
fish: 5,
addFish: () => set((s) => ({ fish: s.fish + 1 })),
}))
// In components, you can use both stores safely
function Zoo() {
const { bears, addBear } = useBearStore()
const { fish, addFish } = useFishStore()
return (
<div>
<div>
{bears} bears and {fish} fish
</div>
<button onClick={addBear}>Add bear</button>
<button onClick={addFish}>Add fish</button>
</div>
)
}
Zustand together with TypeScript provides a balance: you keep the simplicity of small, minimalistic stores, while gaining the safety of strong typing.
You donāt need boilerplate or complex patterns - state and actions live side by side, fully typed, and ready to use.
Start with a basic store to learn the pattern, then expand gradually: use combine for cleaner inference, persist for storage, and devtools for debugging.