init-redux-full.jsx

function initRedux(reducer, initialState) {
    const StateContext = React.createContext(null)
    const DispatchContext = React.createContext(null)

    function Provider(props) {
        const [appState, dispatch] = React.useReducer(reducer, initialState)
        return (
            <StateContext.Provider value={appState}>
                <DispatchContext.Provider value={dispatch}>
                    {props.children}
                </DispatchContext.Provider>
            </StateContext.Provider>
        )
    }

    function useRedux(extractState, actionMap) {
        const appState = React.useContext(StateContext)
        const dispatch = React.useContext(DispatchContext)

        const stateExtract = extractState(appState)

        const actions = Object.keys(actionMap).reduce((acc, key) => {
            const actionCreator = actionMap[key]
            const fn = (...args) => {
                const action = actionCreator(...args)
                if (typeof action === 'function') {
                    action(dispatch, () => appState)
                } else {
                    dispatch(action)
                }
            }
            return { ...acc, [key]: fn }
        }, {})

        return [stateExtract, actions]
    }

    return { Provider, useRedux }
}