ES6ContactStore.js

var contacts = {};

var handleAddContact = (action) => {
  contacts.assign(contacts, action.contact);
  ContactsStore.emitChange();
}

var handleRemoveContact = (action) => {
  var updatedContacts = state.contacts.filter((contact) => {
    return contact.id !== action.contact.id;
  });
  contacts = updatedContacts;
  ContactsStore.emitChange();
}

var actions = {
  [ActionTypes.ADD_CONTACT]: handleAddContact,
  [ActionTypes.DELETE_CONTACT]: handleRemoveContact
}

var ContactsStore = assign({}, EventEmitter.prototype, {
  emitChange() {
    this.emit(StoreEvents.CHANGE);
  },
  getContacts() {
    return contacts;
  }
});

ContactsStore.dispatchToken = AppDispatcher.register((action) => {
  actions[action.type] && actions[action.type].call(this,action)
});

module.exports = ContactsStore;