const counter = (state = 0, action) => {

  switch (action.type) {

    case 'INCREMENT':

      return state + 1;

    case 'DECREMENT':

      return state - 1;

    default:

      return state;

  }

};

​

const Counter = ({

  value,

  onIncrement,

  onDecrement

}) => (

  <div>

    <h1>{value}</h1>

    <button onClick={onIncrement}>+</button>

    <button onClick={onDecrement}>-</button>

  </div>

);

​

const { createStore } = Redux;

const store = createStore(counter);

​

const render = () => {

  ReactDOM.render(

    <Counter 

      value={store.getState()}

      onIncrement={() =>

        store.dispatch({

          type: 'INCREMENT'

        })

      }

      onDecrement={() =>

        store.dispatch({

          type: 'DECREMENT'

        })

      }

    />,

    document.getElementById('root')

  );

};

​

store.subscribe(render);

render();