Troubleshooting React (https://www.reddit.com/r/reactjs/comments/3t7vth/reactrouter_questions/)

actioncreators.js

export function enterRoom(id) {
  return {
    type: 'ENTER_ROOM',
    payload: {
      roomId: id
    }
  };
}

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import Router, {Route} from 'react-router';
import App from './components/App';
import reducer from './reducer';
import {compose, createStore} from 'redux';
import {Provider} from 'react-redux';
import {LobbyContainer} from './components/Lobby';
import {RoomContainer} from './components/Room';
import {devTools, persistState} from 'redux-devtools';
import {DevTools, DebugPanel, LogMonitor} from 'redux-devtools/lib/react';

require('./css/reset.css');
require('./css/style.css');

const finalCreateStore = compose(
  // Provides support for DevTools:
  devTools(),
  // Lets you write ?debug_session=<name> in address bar to persist debug sessions
  persistState(window.location.href.match(/[?&]debug_session=([^&]+)\b/))
)(createStore);

const store = finalCreateStore(reducer);

reducer.js

import {List, Map, fromJS} from 'immutable';

function enterRoom(state, roomId) {
  const availableRooms = state.get('availableRooms');
  var roomEntered = availableRooms.map(room => {
    if (room.get('_id') == roomId) {
      return room;
    }
  });
  var newState = state.set('currentRoom', roomEntered.get(0));
  return newState;
}

export default function(state = Map(), action) {
  switch (action.type) {
    case 'ENTER_ROOM':
      return enterRoom(state, action.payload.roomId);
  }
  return state;
}

Room.js

import React from 'react';
import PureRenderMixin from 'react-addons-pure-render-mixin';
import {connect} from 'react-redux';
import * as actionCreators from '../actioncreators/Room';

export const Room = React.createClass({
  mixins: [PureRenderMixin],
  componentWillMount: function() {
    this.props.enterRoom(this.props.params.id);
  },
  render: function() {
    return (
      <div>
        <h1>Room:</h1>
        {this.props.room.name}
      </div>
    );
  }
});

function mapStateToProps(state) {
  return {
    room: state.get('currentRoom')
  };
}

export const RoomContainer = connect(
  mapStateToProps,
  actionCreators
)(Room);