How to reset state

The following pattern can be used to reset the state to its initial value.

import { create } from 'zustand'

// define types for state values and actions separately
type State = {
  salmon: number
  tuna: number
}

type Actions = {
  addSalmon: (qty: number) => void
  addTuna: (qty: number) => void
  reset: () => void
}

// define the initial state
const initialState: State = {
  salmon: 0,
  tuna: 0,
}

// create store
const useSlice = create<State & Actions>()((set, get) => ({
  ...initialState,
  addSalmon: (qty: number) => {
    set({ salmon: get().salmon + qty })
  },
  addTuna: (qty: number) => {
    set({ tuna: get().tuna + qty })
  },
  reset: () => {
    set(initialState)
  },
}))

Resetting multiple stores at once

import { create as _create } from 'zustand'
import type { StateCreator } from 'zustand'

const storeResetFns = new Set<() => void>()

const resetAllStores = () => {
  storeResetFns.forEach((resetFn) => {
    resetFn()
  })
}

export const create = (<T extends unknown>() => {
  return (stateCreator: StateCreator<T>) => {
    const store = _create(stateCreator)
    const initialState = store.getState()
    storeResetFns.add(() => {
      store.setState(initialState, true)
    })
    return store
  }
}) as typeof _create

Resetting bound store using Slices pattern

import create from 'zustand'
import type { StateCreator } from 'zustand'

const sliceResetFns = new Set<() => void>()

export const resetAllSlices = () => {
  sliceResetFns.forEach((resetFn) => {
    resetFn()
  })
}

const initialBearState = { bears: 0 }

interface BearSlice {
  bears: number
  addBear: () => void
  eatFish: () => void
}

const createBearSlice: StateCreator<
  BearSlice & FishSlice,
  [],
  [],
  BearSlice
> = (set) => {
  sliceResetFns.add(() => set(initialBearState))
  return {
    ...initialBearState,
    addBear: () => set((state) => ({ bears: state.bears + 1 })),
    eatFish: () => set((state) => ({ fishes: state.fishes - 1 })),
  }
}

const initialStateFish = { fishes: 0 }

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

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

const useBoundStore = create<BearSlice & FishSlice>()((...a) => ({
  ...createBearSlice(...a),
  ...createFishSlice(...a),
}))

export default useBoundStore

CodeSandbox Demo