React redux connect implementation using react hooks.

App.js

import React from 'react';
import useStore from './useStore';
import Todo from './Todo'
import { todoActions } from './actions';

export default () => {
  const [
    todos,
    { addTodo, rmTodo }
  ] = useStore(store => store.todos, todoActions)
  
  return <div>{ todos.map((todo, i) => <Todo key={i} todo={todo} />) }</div>
}

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from './useStore';
import createStore from './store';
import App from './App';

ReactDOM.render(
  <Provider store={createStore()}>
    <App />
  </Provider>, 
  document.getElementById('root')
);

useStore.js

import React, { useState, useContext, useEffect, createContext } from "react"
import { bindActionCreators } from "redux"

const context = createContext()

const isFn = (fn) => typeof fn === "function"

const mapStateFactory = (selector) => isFn(selector) ? selector : () => ({})

const mapDispatchFactory = (actions, dispatch) =>
  isFn(actions)
  ? actions(dispatch)
  : bindActionCreators(actions, dispatch)

export default function (mapState, mapDispatch) {
  const { getState, dispatch, subscribe } = useContext(context).store

  const mapStateEffect = mapStateFactory(mapState)
  const actions = mapDispatchFactory(mapDispatch, dispatch)

  const currentWorkingState = () => mapStateEffect(getState())
  const [state, setState] = useState(currentWorkingState())

  useEffect(() =>
    subscribe(() => {
      const newState = currentWorkingState()
      if (state !== newState) {
        setState(newState)
      }
    }), [])

  return [state, actions]
}

export const Provider = ({ store, children }) => <context.Provider value={{ store }}>{children}</context.Provider>