index.js

import React from 'react'
import ReactDOM from 'react-dom'
import './index.css'
import App from './App'
import * as serviceWorker from './serviceWorker'
import { createStore, applyMiddleware, compose } from 'redux'
import rootReducer from './store/reducers/rootReducer'
import { Provider } from 'react-redux'
import thunk from 'redux-thunk'
import { getFirestore, reduxFirestore } from 'redux-firestore'
import { getFirebase, reactReduxFirebase } from 'react-redux-firebase'
import fbConfig from './config/fbConfig'

const store = createStore(
    rootReducer, 
    compose(
        applyMiddleware(thunk.withExtraArgument({ getFirebase, getFirestore })),
        reduxFirestore(fbConfig),
        reactReduxFirebase(fbConfig)
    )
)

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

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();