text: import { combineReducers } from 'redux';
  import BooksReducer from './reducer_books';
  import ActiveBookReducer from './reducer_active_book';
  import ModalsReducer from './reducer_modals';
  import SearchReducer from './reducer_search';
  import undoable, { distinctState } from 'redux-undo';
  
  
  const undoableBooksReducer = undoable(BooksReducer, {
      filter: distinctState()
  });
  
  const undoableActiveBookReducer = undoable(ActiveBookReducer, {
      filter: distinctState()
  })
  
  const rootReducer = combineReducers({
    books: undoableBooksReducer,
    activeBook: ActiveBookReducer,
    modals: ModalsReducer,
    search: SearchReducer
  });
  
  const undoableReducer = undoable(rootReducer, {
      filter: distinctState()
  })
  
  export default rootReducer;
  