Simple counter app with redux

reduxcounter.js

import React from 'react';
import ReactDOM from 'react-dom';
import { createStore } from 'redux';

const counterReducer = (state = 0,action) => {
switch(action.type){
  case 'INCREMENT':
    return state + 1
  case 'DECREMENT':
    return state - 1
  case 'ZERO':
    return 0
    default:
    return state
  }
}
const store = createStore(counterReducer)

const App = () => {
  return (
    <div>
      <div>
        {store.getState()}
      </div>
      <button
      onClick={e => store.dispatch({type:'INCREMENT'})}
      >
        plus
        </button>       

        <button
      onClick={e => store.dispatch({type:'DECREMENT'})}
      >
        minus
        </button> 

        <button
      onClick={e => store.dispatch({type:'ZERO'})}
      >
        zero
        </button> 
    </div>
  );
}

const renderApp = () => {
  ReactDOM.render(
    <App />,
  document.getElementById('root')
)}

renderApp()
store.subscribe(renderApp)