text: import {SHOW_BOOK_LIST} from '../actions/index';
  import {SHOW_BOOK_DETAILS} from '../actions/index';
  
  export function ReducerCurrentContent(state = null, action) {
      switch (action.type) {
          case SHOW_BOOK_LIST:
              return 'book_list';
          case SHOW_BOOK_DETAILS:
              return "book_details";
          default:
              return state;
      }
  }
  