Avoid duplicating nested objects in redux store

Question

I'm giving redux-orm a try and from what I can gather, redux-orm creates an object in store, whose key is the value specified via Model.name, for every registered model.

Well,to create my "entities" reducer, I'm using combineReducers, passing in the reducers for all my entities, like this:

import { combineReducers } from 'redux';
import City from './cityReducer';
import Poi from './pointOfInterestReducer';

const entitiesReducer = combineReducers({
  City,
  Poi
});

export default entitiesReducer;

And finally this is how I create my rootReducer, also using combineReducers:

The problem is that,I think that, by using combineReducers I'm duplicating the keys in my store like it's shown here:

Do you have any idea how I can avoid this, and have all my models be direct descendants of "entities"?

Something like entities>City and not entities>City>City

Edit: cityReducer.js

import orm from './../../orm/orm';
import * as types from '../../actions/actionTypes';

const loadCities = (state, action) => {
  // Create a Redux-ORM session from our entities "tables"
  const session = orm.session(state);
  // Get a reference to the correct version of model classes for this Session
  const { City } = session;
  const { cities } = action.payload;

  // Clear out any existing models from state so that we can avoid
  // conflicts from the new data coming in if data is reloaded

  City.all().toModelArray().forEach(city => city.delete());


  // Immutably update the session state as we insert items
  cities.forEach(city => City.parse(city));  
  return session.state;
};

const updateCity = (state, payload) => {
  const { id, newItemAttributes } = payload;

  const session = orm.session(state);
  const { City } = session;

  if (City.hasId(id)) {
    const modelInstance = City.withId(id);

    modelInstance.update(newItemAttributes);
  }

  return session.state;
};


const deleteCity = (state, payload) => {
  const { id } = payload;

  const session = orm.session(state);
  const { City } = session;

  if (City.hasId(id)) {
    const modelInstance = City.withId(id);

    // The session will immutably update its state reference
    modelInstance.delete();
  }

  return session.state;
};

const createCity = (state, payload) => {
  const { city } = payload;

  const session = orm.session(state);
  const { City } = session;

  City.parse(city);

  return session.state;
};

const citiesReducer = (dbState, action) => {
  const session = orm.session(dbState);
  switch (action.type) {
    case types.LOAD_CITIES_SUCCESS: return loadCities(dbState, action);
    case types.CREATE_CITY_SUCCESS: return createCity(dbState, action);
    case types.UPDATE_CITY_SUCCESS: return updateCity(dbState, action);
    case types.DELETE_CITY_SUCCESS: return deleteCity(dbState, action);
    default: return session.state;
  }
};

export default citiesReducer;

Answer 1

There's two ways you can use Redux-ORM to define its "tables" structure, and write reducer logic to use those tables. I gave examples of both approaches in my blog posts Practical Redux, Part 1: Redux-ORM Basics, Practical Redux, Part 2: Redux-ORM Concepts and Techniques, and Practical Redux, Part 5: Loading and Displaying Data. (Note that those posts cover use of Redux-ORM 0.8, and version 0.9 has some API changes. I listed those changes in Practical Redux, Part 9.)

The first approach is to write your reducer logic attached to your model classes, and use the Redux-ORM ORM instance to generate a reducer that creates the "tables" and manages them for you. Per the example on the front of the Redux-ORM repo:

import {createReducer} from "redux-orm";
import {orm} from "./models";

const rootReducer = combineReducers({
    entities: createReducer(orm)
});

The other approach is to write your own function that creates the initial state, and possibly other functions that handle the updating:

import {orm} from "./models";

const initialState = orm.getEmptyState();

export default function entitiesReducer(state = initialState, action) {
    // handle other actions here if desired
    return state;
}

In other words, don't define the separate per-model-type "tables" yourself. Let Redux-ORM define those, either automatically in its own reducer, or by using it to generate the initial state for your entities reducer.