ReduxIntro4

import { createStore } from 'redux';

//  Store  
const dataStore = createStore(r, {
  beerlist: {
    name: 'IPA',
    abv: 7.4
  },
  beersOnTap: 1,
  liveMusicHistory: {
    bandName: 'Bahamas',
    gigDate: '2017-01-01'
  },
  ...
});

//  Reducers 
const beerlistReducer = (state, action){
  switch(action.type){
    case 'CHANGE_BEER_NAME': {
      state = {...state, name: action.payload}//  Create new state object
      break;
    }
    case 'CHANGE_BEER_ABV': {
      state = {...state, abv: action.payload}//  Create new state object
      break;
    }
  }
  return state;
}

const beersOnTapReducer = (state, action){
...
}

const liveMusicHistoryReducer = (state, action){
...
}

const reducers = combineReducers({
  beerlist: beerlistReducer,
  beersOnTap: beersOnTapReducer,
  liveMusicHistory: liveMusicHistoryReducer
})

//  Actions 
//  Action dispatched to your Store
dataStore.dispatch({ type: 'CHANGE_BEER_NAME', payload: 'Stout' });
dataStore.dispatch({ type: 'CHANGE_BEER_ABV', payload: 5.9 });

//  Called any time an action is dispatched
dataStore.subscribe(());