Ejemplo de store con redux.

store-example.js

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

// Preparamos nuestra funcion reducer
const myReducer = (state = 0, action) => {
  switch(action.type) {
    case 'sumar':
      return state + 1;
    case 'restar':
      return state - 1;
    default:
      return state;
  }
}

// Inicializamos el store pasándole el reducer
const store = createStore(myReducer);

// Creamos nuestro componente de react
const counter = ({value, clickSumar, clickRestar}) => {
  <div>
    <h1>{value}</h1>
    <button onClick={clickSumar}>Sumar</button>
    <button onClick={clickRestar}>Restar</button>
  </div>
};

// Renderizamos el componente.
// Cada vez que el stado cambie, el componente
// se volverá a renderizar.
const render = () => {
  ReactDOM.render(
    <Counter 
      value={store.getState()}
      clickSumar={ ()=> store.dispatch({type: 'sumar'}) }
      clickRestar={ ()=> store.dispatch({type: 'restar'}) }
    />,
    document.getElementById('MyAppContainer');
  );
};

store.subscribe(render);
render();

Line 39: Parsing error: Unexpected token, expected ","

37 | clickRestar={ ()=> store.dispatch({type: 'restar'}) }
38 | />,

39 | document.getElementById('MyAppContainer');
| ^
40 | );
41 | };
42 |