Zustand state management for React and vanilla JavaScript. Use when creating stores, using selectors, persisting state to localStorage, integrating devtools, or managing global state without Redux complexity. Triggers on zustand, create(), createStore, useStore, persist, devtools, immer middleware.
Minimal state management - no providers, minimal boilerplate.
import { create } from 'zustand'
interface BearState {
bears: number
increase: (by: number) => void
}
const useBearStore = create<BearState>()((set) => ({
bears: 0,
increase: (by) => set((state) => ({ bears: state.bears + by })),
}))
// In component - select only what you need
const bears = useBearStore((state) => state.bears)
const increase = useBearStore((state) => state.increase)
// Flat updates (auto-merged at one level)
set({ bears: 5 })
set((state) => ({ bears: state.bears + 1 }))
// Nested objects (manual spread required)
set((state) => ({
nested: { ...state.nested, count: state.nested.count + 1 }
}))
// Replace entire state (no merge)
set({ bears: 0 }, true)
// Good - subscribes only to bears
const bears = useBearStore((state) => state.bears)
// Bad - rerenders on any change
const state = useBearStore()
// Multiple values with useShallow (prevents rerenders with shallow comparison)
import { useShallow } from 'zustand/react/shallow'
const { bears, fish } = useBearStore(
useShallow((state) => ({ bears: state.bears, fish: state.fish }))
)
// Array destructuring also works
const [bears, fish] = useBearStore(
useShallow((state) => [state.bears, state.fish])
)
// Get current state (non-reactive)
const state = useBearStore.getState()
// Update state
useBearStore.setState({ bears: 5 })
// Subscribe to changes
const unsub = useBearStore.subscribe((state) => console.log(state))
unsub() // unsubscribe
import { createStore } from 'zustand/vanilla'
const store = createStore((set) => ({
bears: 0,
increase: (by) => set((state) => ({ bears: state.bears + by })),
}))
store.getState().bears
store.setState({ bears: 10 })
store.subscribe((state) => console.log(state))
| Pattern | When to Use |
|---|---|
| Single selector | One piece of state needed |
useShallow | Multiple values, avoid rerenders |
getState() | Outside React, event handlers |
subscribe() | External systems, logging |
| Vanilla store | Non-React environments |