client.render.js

import React from 'react';
import Router from 'react-router';
import routes from './routes';
import { createStore, combineReducers } from 'redux';
import { Provider } from 'react-redux';

import intlReducer from './intl/intl.reducer'

const app = document.getElementById('app');
/** initalState contains very complicated object with all translations */
const initialState = window._initialState;

const reducer = combineReducers({ intl: intlReducer });
const createStoreWithMiddleware = applyMiddleware(thunk)(createStore);
const store = createStoreWithMiddleware(reducer, initialState);

Router.run(routes, Router.HistoryLocation, (Handler) => {
  React.render(
    <Provider store={store}>
      {() => <Handler />}
    </Provider>, app);
});

header.react.js

import React from 'react';

export default class Header extends React.Component {
  static propTypes = {
    msg: React.PropTypes.object.isRequired
  };
  render() {
    const {msg} = this.props;
    return (
      <header>
        {/* initially there is no app.header, because reducer trigger dummy action with empty object as initial state */}
        {msg.app.header}
      </header>
    );
  }
}

intl.reducer.js

/** i can't provide initial state, that has the same structure as translation object, because it's realy big and has multiple levels */
var initialState = {};

export default function intl(state = initialState) {
  return state;
}