Reflux - handling ajax errors on creation

TodoActions.js

var Reflux = require('reflux'),
    _ = require('underscore'),
    api = require('./api');

var TodoActions = Reflux.createActions(['create', 'created', 'errored']);

TodoActions.create.preEmit = function(data) {
 data = _.extend({_iid: _.uniqueId('todo_')}, data);
 api.createTodo(data).then(function(todo) { TodoActions.created(_.extend({_iid: data._iid}, todo)); })
                     .catch(function(err) { TodoActions.errored(_.extend({_iid: data._iid}, {_error: err}))});
 return data;
}

module.exports = TodoActions;

TodoStore.js

var Reflux = require('reflux'),
    _ = require('underscore'),
    TodoActions = require('./TodoActions');

module.exports = Reflux.createStore({
 listenables: TodoActions,
 todos: [],
 findTodo: function(data) {
  return _.find(this.todos, function(one) { return one.id ? one.id === data.id : one._iid === data._iid; });
 }
 onCreate: function(todo) {
  this.todos.push(_.extend(todo, {_persisting: true}));
  this.trigger(this.todos);
 },
 onErrored: function(todo) {
  var existing = this.findTodo(todo);
  if (!existing) return;
  this.todos[this.todos.indexOf(existing)] = _.extend(_.omit(existing, '_persisting'), todo);
  this.trigger(this.todos);
 },
 onCreated: function(todo) {
  var existing = this.findTodo(todo);
  if (!existing) return;
  this.todos[this.todos.indexOf(existing)] = todo;
  this.trigger(this.todos);
 }
});