如果一个javascript变量位于类之外，但位于模块的闭包内，它是否私有？

我从https://facebook.github.io/flux/docs/todo-list.html#content遇到了以下代码，并遇到了这个问题，因为该网站宣布

该对象（_todos）包含所有单独的待办事项。因为此变量位于类之外，但在模块的关闭之内，所以它保持私有状态-不能从模块外部直接更改。

这是真的？据我所知，似乎_todos是一个全局对象。

var AppDispatcher = require('../dispatcher/AppDispatcher');
var EventEmitter = require('events').EventEmitter;
var TodoConstants = require('../constants/TodoConstants');
var assign = require('object-assign');

var CHANGE_EVENT = 'change';

var _todos = {}; // collection of todo items

/**
 * Create a TODO item.
 * @param {string} text The content of the TODO
 */
function create(text) {
  // Using the current timestamp in place of a real id.
  var id = Date.now();
  _todos[id] = {
    id: id,
    complete: false,
    text: text
  };
}

/**
 * Delete a TODO item.
 * @param {string} id
 */
function destroy(id) {
  delete _todos[id];
}

var TodoStore = assign({}, EventEmitter.prototype, {

  /**
   * Get the entire collection of TODOs.
   * @return {object}
   */
  getAll: function() {
    return _todos;
  },

  emitChange: function() {
    this.emit(CHANGE_EVENT);
  },

  /**
   * @param {function} callback
   */
  addChangeListener: function(callback) {
    this.on(CHANGE_EVENT, callback);
  },

  /**
   * @param {function} callback
   */
  removeChangeListener: function(callback) {
    this.removeListener(CHANGE_EVENT, callback);
  },

      dispatcherIndex: AppDispatcher.register(function(payload) {
        var action = payload.action;
        var text;

        switch(action.actionType) {
          case TodoConstants.TODO_CREATE:
            text = action.text.trim();
            if (text !== '') {
              create(text);
              TodoStore.emitChange();
            }
            break;

          case TodoConstants.TODO_DESTROY:
            destroy(action.id);
            TodoStore.emitChange();
            break;

          // add more cases for other actionTypes, like TODO_UPDATE, etc.
        }

        return true; // No errors. Needed by promise in Dispatcher.
      })

})    ;

module.exports = TodoStore;