Simple logger

function loggerMiddleware(store) {
  return function(next) {
    return function(action) {
      console.log('dispatching', action);
      let result = next(action);
      console.log('next state', store.getState());
      return result;
    }
  }
}

import { createStore, applyMiddleware } from 'redux';

const store = createStore(reducer, applyMiddleware(loggerMiddleware));