gistfile1.txt

import React from 'react'
import immer from 'immer'
//

export default function makeStore() {
  // Create a context for this store
  const context = React.createContext()

  let store = {}

  const Provider = ({ children, initialState = {} }) => {
    const [state, preSetState] = React.useState(() => initialState)

    const setState = React.useCallback(
      updater =>
        preSetState(old => {
          const newState = immer(old, draft => updater(draft))
          return newState
        }),
      [preSetState]
    )

    store.state = state

    const contextValue = React.useMemo(() => [state, setState], [
      setState,
      state,
    ])

    return <context.Provider value={contextValue}>{children}</context.Provider>
  }

  const useStore = () => React.useContext(context)

  store.Provider = Provider
  store.useStore = useStore

  return store
}