drupalcampbristol/core/modules/toolbar/js/models/MenuModel.js

/**
 * @file
 * A Backbone Model for collapsible menus.
 */

(function (Backbone, Drupal) {

  'use strict';

  /**
   * Backbone Model for collapsible menus.
   *
   * @constructor
   *
   * @augments Backbone.Model
   */
  Drupal.toolbar.MenuModel = Backbone.Model.extend(/** @lends Drupal.toolbar.MenuModel# */{

    /**
     * @type {object}
     *
     * @prop {object} subtrees
     */
    defaults: /** @lends Drupal.toolbar.MenuModel# */{

      /**
       * @type {object}
       */
      subtrees: {}
    }
  });

}(Backbone, Drupal));