Cannot use combineForms in my existing combineReducers

Following the react-boiler-plate project, I want to use react-redux-forms and looking at the 'get started' guide it says to just use combineForms. I tried to figure this out for many hours and the documentation is not helping much. Hope somebody can clue me in to what's happening here.

My hours of research has led me to believe that:

I have incorrectly used combineForms
ImmutableJS cannot be used in conjunction with react-redux-forms

Here are my files:

configureStore.js:

/** * Create the store with dynamic reducers */

import {createStore, applyMiddleware, compose} from 'redux';
import {fromJS} from 'immutable';
import {routerMiddleware} from 'react-router-redux';
import createSagaMiddleware from 'redux-saga';
import createReducer from './reducers';


const sagaMiddleware = createSagaMiddleware();

export default function configureStore(initialState = {}, history) {
  // Create the store with two middlewares
  // 1. sagaMiddleware: Makes redux-sagas work
  // 2. routerMiddleware: Syncs the location/URL path to the state
  const middlewares = [
    sagaMiddleware,
    routerMiddleware(history),
  ];

  const enhancers = [
    applyMiddleware(...middlewares),
  ];

  // If Redux DevTools Extension is installed use it, otherwise use Redux compose
  /* eslint-disable no-underscore-dangle */
  const composeEnhancers =
    process.env.NODE_ENV !== 'production' &&
    typeof window === 'object' &&
    window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__
      ? window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__({
        // TODO Try to remove when `react-router-redux` is out of beta, LOCATION_CHANGE should not be fired more than once after hot reloading
        // Prevent recomputing reducers for `replaceReducer`
        shouldHotReload: false,
      })
      : compose;
  /* eslint-enable */


  const store = createStore(
    createReducer(),
    fromJS(initialState),
    composeEnhancers(...enhancers)
  );

  // Extensions
  store.runSaga = sagaMiddleware.run;
  store.injectedReducers = {}; // Reducer registry
  store.injectedSagas = {}; // Saga registry

  // Make reducers hot reloadable, see http://mxs.is/googmo
  /* istanbul ignore next */
  if (module.hot) {
    module.hot.accept('./reducers', () => {
      store.replaceReducer(createReducer(store.injectedReducers));
    });
  }

  return store;
}

reducer.js:

import { combineReducers } from 'redux-immutable';
import { fromJS } from 'immutable';
import { LOCATION_CHANGE } from 'react-router-redux';
import { createForms, combineForms } from 'react-redux-form/immutable';
import languageProviderReducer from 'containers/LanguageProvider/reducer';

/*
 * routeReducer
 *
 * The reducer merges route location changes into our immutable state.
 * The change is necessitated by moving to react-router-redux@4
 *
 */

// Initial routing state
const routeInitialState = fromJS({
  location: null,
});

/**
 * Merge route into the global application state
 */
function routeReducer(state = routeInitialState, action) {
  switch (action.type) {
    /* istanbul ignore next */
    case LOCATION_CHANGE:
      return state.merge({
        location: action.payload,
      });
    default:
      return state;
  }
}

const initialUserState = fromJS({
  firstName: '',
  lastName: '',
});


/**
 * Creates the main reducer with the dynamically injected ones
 */
export default function createReducer(injectedReducers) {
  return combineReducers({
    route: routeReducer,
    language: languageProviderReducer,
    forms: combineForms({
      user: initialUserState,
    }, 'forms'),
    ...injectedReducers,
  });
}

index.js:

import React from 'react';
import {
  Form,
  Control,
} from 'react-redux-form';


export default function App() {
  return (
    <UserForm />
  );
}

class UserForm extends React.Component {
  render() {
    return (
      <Form
        model="user"
        onSubmit={(user) => this.handleSubmit(user)}
      >
        <label>First name:</label>
        <Control.text model=".firstName" />
        <button type="submit">
          Finish registration!
        </button>
      </Form>
    );
  }
}

app.js:

/**
 * app.js
 *
 * This is the entry file for the application, only setup and boilerplate
 * code.
 */

// Needed for redux-saga es6 generator support
import 'babel-polyfill';

// Import all the third party stuff
import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import { ConnectedRouter } from 'react-router-redux';
import FontFaceObserver from 'fontfaceobserver';
import createHistory from 'history/createBrowserHistory';
import 'sanitize.css/sanitize.css';

// Import root app
import App from 'containers/App';

// Import Language Provider
import LanguageProvider from 'containers/LanguageProvider';

// Load the favicon, the manifest.json file and the .htaccess file
/* eslint-disable import/no-webpack-loader-syntax */
import '!file-loader?name=[name].[ext]!./images/favicon.ico';
import '!file-loader?name=[name].[ext]!./images/icon-72x72.png';
import '!file-loader?name=[name].[ext]!./images/icon-96x96.png';
import '!file-loader?name=[name].[ext]!./images/icon-120x120.png';
import '!file-loader?name=[name].[ext]!./images/icon-128x128.png';
import '!file-loader?name=[name].[ext]!./images/icon-144x144.png';
import '!file-loader?name=[name].[ext]!./images/icon-152x152.png';
import '!file-loader?name=[name].[ext]!./images/icon-167x167.png';
import '!file-loader?name=[name].[ext]!./images/icon-180x180.png';
import '!file-loader?name=[name].[ext]!./images/icon-192x192.png';
import '!file-loader?name=[name].[ext]!./images/icon-384x384.png';
import '!file-loader?name=[name].[ext]!./images/icon-512x512.png';
import '!file-loader?name=[name].[ext]!./manifest.json';
import 'file-loader?name=[name].[ext]!./.htaccess'; // eslint-disable-line import/extensions
/* eslint-enable import/no-webpack-loader-syntax */

import configureStore from './configureStore';

// Import i18n messages
import { translationMessages } from './i18n';

// Import CSS reset and Global Styles
import './global-styles';

// Observe loading of Open Sans (to remove open sans, remove the <link> tag in
// the index.html file and this observer)
const openSansObserver = new FontFaceObserver('Open Sans', {});

// When Open Sans is loaded, add a font-family using Open Sans to the body
openSansObserver.load().then(() => {
  document.body.classList.add('fontLoaded');
}, () => {
  document.body.classList.remove('fontLoaded');
});

// Create redux store with history
const initialState = {};
const history = createHistory();
const store = configureStore(initialState, history);
const MOUNT_NODE = document.getElementById('app');

const render = (messages) => {
  ReactDOM.render(
    <Provider store={store}>
      <LanguageProvider messages={messages}>
        <ConnectedRouter history={history}>
          <App />
        </ConnectedRouter>
      </LanguageProvider>
    </Provider>,
    MOUNT_NODE
  );
};

if (module.hot) {
  // Hot reloadable React components and translation json files
  // modules.hot.accept does not accept dynamic dependencies,
  // have to be constants at compile-time
  module.hot.accept(['./i18n', 'containers/App'], () => {
    ReactDOM.unmountComponentAtNode(MOUNT_NODE);
    render(translationMessages);
  });
}

// Chunked polyfill for browsers without Intl support
if (!window.Intl) {
  (new Promise((resolve) => {
    resolve(import('intl'));
  }))
    .then(() => Promise.all([
      import('intl/locale-data/jsonp/en.js'),
      import('intl/locale-data/jsonp/de.js'),
    ]))
    .then(() => render(translationMessages))
    .catch((err) => {
      throw err;
    });
} else {
  render(translationMessages);
}

// Install ServiceWorker and AppCache in the end since
// it's not most important operation and if main code fails,
// we do not want it installed
if (process.env.NODE_ENV === 'production') {
  require('offline-plugin/runtime').install(); // eslint-disable-line global-require
}

Most of the code is almost untouched after cloning it from react-boiler-plate, only changed index.js to just have the form and modified reducer.js as well.

I can see from redux dev tools that I have the form keys:

but the error message I get is and the app won't load:

Thanks a MILLION in advance!

Solution

Finally figured this out. Because I was using immutableJS, all I had to do was change the import from:

import { Form, Control } from 'react-redux-form';

to:

import { Form, Control } from 'react-redux-form/immutable';