import { createStore } from 'redux';
// Forbids to change the object structure
const initialState = Object.freeze({
    title: 'Beautiful Code',
    author: 'Douglas Crockford'
});
 
// State updater
function reducer(book = initialState, action) {
  switch (action.type) {
    case 'CHANGE_BOOK_TITLE':
      return {
        ...book,
        title: action.title
      }
    default:
      return book
  }
}
// Events listener that occour on the state
const store = createStore(reducer);
store.subscribe(function(){
  console.log(store.getState());
});
// Dispatch changes on the state
store.dispatch({ type: 'CHANGE_BOOK_TITLE', title: 'JavaScript The Best Parts' });
store.dispatch({ type: 'CHANGE_BOOK_TITLE', title: 'How JavaScript Works' });