LibraryStore.js

var STATE = {
      books: new Backbone.Collection([], {
        model: Models.BOOK_MODEL
      }),
      users: new Backbone.Collection([], {
        model: Models.USER_MODEL
      }),
      categories: new Backbone.Collection([], {
        model: Models.CATEGORY_MODEL
      })
    };

// ===========================================
// ================= METHODS =================
// ===========================================

function _processBookResults(dfd, snapshot) {
  var bookModels,
      BookCollection = Models.newCollection(Models.BOOK_MODEL);
  bookModels = [].map.call(snapshot.val(), function(book) {
    return Models.createNewBook(book);
  });
  STATE.books = new BookCollection(bookModels);
  dfd.resolve();
}

function _processUserResults(dfd, snapshot) {
  var userModels,
      UserCollection = Models.newCollection(Models.USER_MODEL);
  userModels = [].map.call(snapshot.val(), function (user) {
    return Models.createNewUser(user);
  });
  STATE.users = new UserCollection(userModels);
  dfd.resolve();
}

function _processCategoryResults(dfd, snapshot) {
  var categoryModels,
      CategoryCollection = Models.newCollection(Models.CATEGORY_MODEL);
  categoryModels = [].map.call(snapshot.val(), function (category) {
    return Models.createNewCategory(category);
  });
  STATE.categories = new CategoryCollection(categoryModels);
  dfd.resolve();
}

function _loadBooks(dfd) {
  REFS.BOOKS.once('value',
    _processBookResults.bind(null, dfd),
    _handleError.bind(null, dfd)
  );
}

function _loadUsers(dfd) {
  REFS.USERS.once('value',
    _processUserResults.bind(null, dfd),
    _handleError.bind(null, dfd)
  );
}

function _loadCategories(dfd) {
  REFS.CATEGORIES.once('value',
    _processCategoryResults.bind(null, dfd),
    _handleError.bind(null, dfd)
  );
}

function _updateBooks(snapshot) {
  var bookModels = [].map.call(snapshot.val(), function(book) {
    return Models.createNewBook(book);
  });
  STATE.books.reset(bookModels);
  LibraryStore.emitChange();
}

function _init() {

  var loadBooksDeferred = new jQuery.Deferred(),
      loadUsersDeferred = new jQuery.Deferred(),
      loadCategoriesDeferred = new jQuery.Deferred(),
      stateReadyDfd = new jQuery.Deferred(),
      credentials = SessionStore.getState();

  sessionStorage.setItem('username', credentials.userName);

  _loadBooks(loadBooksDeferred);
  _loadUsers(loadUsersDeferred);
  _loadCategories(loadCategoriesDeferred);

  jQuery
    .when(loadBooksDeferred, loadUsersDeferred, loadCategoriesDeferred)
    .then(stateReadyDfd.resolve, stateReadyDfd.reject);

  return stateReadyDfd;
}

// ===========================================
// ================== STORE ==================
// ===========================================

LibraryStore = merge(EventEmitter.prototype, {
  getAll: function() {
    return STATE;
  }
});
LibraryStore = merge(LibraryStore, StoreMixin);

// ============================================
// ================= REGISTER =================
// ============================================

LibraryStore.dispatchToken = AppDispatcher.register(function(payload) {
  var action = payload.action;
  switch(action.actionType) {
    case Constants.INITIALIZE:
      _init().done(function() {
        LibraryStore.emitChange();
      });
      break;
    default:
      return true;
  }
  return true;
});

Login.jsx

Login = React.createClass({

  _handleSubmit: function () {
    var inp = this.refs.login.getDOMNode();
    Actions.updateCredentials(inp.value);
    inp.value = '';
  },

  render: function () {
    return (
      <span className="input-group-btn">
        <button className="btn btn-default" type="button" onClick={this._handleSubmit} >
          Login
        </button>
      </span>
    );
  }
});

SessionStore.js

// ===========================================
// ================= METHODS =================
// ===========================================

function _setState(settings, cb) {
  STATE.loggedIn = settings.loggedIn;
  STATE.userName = settings.userName;
  cb();
}

function _handleResult(userName, snapshot) {
  var validUser,
      users;
  users = [].filter.call(snapshot.val(), function(user) {
    return user.login === userName;
  });
  validUser = users.length > 0;
  if (validUser) {
    _setState({
      loggedIn: true,
      userName: userName
    }, Actions.initialize);
  }
}

function _updateCredentials(userName) {
  REFS.USERS.once('value', _handleResult.bind(null, userName));
}

// ===========================================
// ================== STORE ==================
// ===========================================

SessionStore = merge(EventEmitter.prototype, {
  getState: function() {
    return STATE;
  }
});
SessionStore = merge(SessionStore, StoreMixin);

// ============================================
// ================= REGISTER =================
// ============================================

SessionStore.dispatchToken = AppDispatcher.register(function(payload) {
  var action = payload.action;
  switch (action.actionType) {
    case Constants.UPDATE_CREDENTIALS:
      _updateCredentials(action.userName);
      break;
    default:
      return true;
  }
  return true;
});