zustand-v3-create-context.md

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createContext from zustand/context	18

A special createContext is provided since v3.5, which avoids misusing the store hook.

Note: This function is deprecated in v4 and will be removed in v5. See Migration.

import create from 'zustand'
import createContext from 'zustand/context'

const { Provider, useStore } = createContext()

const createStore = () => create(...)

const App = () => (
  <Provider createStore={createStore}>
    ...
  </Provider>
)

const Component = () => {
  const state = useStore()
  const slice = useStore(selector)
  ...

createContext usage in real components

import create from "zustand";
import createContext from "zustand/context";

// Best practice: You can move the below createContext() and createStore to a separate file(store.js) and import the Provider, useStore here/wherever you need.

const { Provider, useStore } = createContext();

const createStore = () =>
  create((set) => ({
    bears: 0,
    increasePopulation: () => set((state) => ({ bears: state.bears + 1 })),
    removeAllBears: () => set({ bears: 0 })
  }));

const Button = () => {
  return (
      {/** store() - This will create a store for each time using the Button component instead of using one store for all components **/}
    <Provider createStore={createStore}>
      <ButtonChild />
    </Provider>
  );
};

const ButtonChild = () => {
  const state = useStore();
  return (
    <div>
      {state.bears}
      <button
        onClick={() => {
          state.increasePopulation();
        }}
      >
        +
      </button>
    </div>
  );
};

export default function App() {
  return (
    <div className="App">
      <Button />
      <Button />
    </div>
  );
}

createContext usage with initialization from props

import create from 'zustand'
import createContext from 'zustand/context'

const { Provider, useStore } = createContext()

export default function App({ initialBears }) {
  return (
    <Provider
      createStore={() =>
        create((set) => ({
          bears: initialBears,
          increase: () => set((state) => ({ bears: state.bears + 1 })),
        }))
      }>
      <Button />
    </Provider>
  )
}

Migration

Discussion: #1276

Here's the diff showing how to migrate from v3 createContext to v4 API.

// store.ts
+ import { createContext, useContext } from "react";
- import create from "zustand";
- import createContext from "zustand/context";
+ import { createStore, useStore } from "zustand";

- const useStore = create((set) => ({
+ const store =  createStore((set) => ({
    bears: 0,
    increasePopulation: () => set((state) => ({ bears: state.bears + 1 })),
    removeAllBears: () => set({ bears: 0 })
  }));

+ const MyContext = createContext()

+ export const Provider = ({ children }) = <MyContext.Provider value={store}>{children}</MyContext.Provider>;

+ export const useMyStore = (selector) => useStore(useContext(MyContext), selector);