old_contents: "use strict";
  
  const _ = require( 'underscore' );
  const Backbone = require( 'backbone' );
  Backbone.LocalStorage = require( "backbone.localstorage" );
  //require( 'backbone-event-logger' );
  
  const VariableModel = require( '../models/dirPickerVariable' );
  
  //noinspection JSUnusedGlobalSymbols
  /**
   * @class
   * @extends {Backbone.Collection}
   */
  const CollectionsDirPickerVariables = Backbone.Collection.extend( {
    localStorage: new Backbone.LocalStorage( "dirPickerVariablesCollection" ),
    model: VariableModel,
    comparator: 'sort',
    initialize: function () {
      //this.debugEvents('CollectionsVariables');
    }
  } );
  _.extend( CollectionsDirPickerVariables.prototype, require( './mixin' ) );
  
  const variables = module.exports = new CollectionsDirPickerVariables();
  variables.fetch();
new_contents: "use strict";
  
  import DirPickerCollectionBase from './dirPickerCollectionBase';
  import BackboneLocalStorage from 'backbone.localstorage';
  import VariableModel from '../models/dirPickerVariable'
  
  /**
   * Variableを束ねるコレクション
   */
  export class DirPickerVariables extends DirPickerCollectionBase {
  
    /**
     * @param {object} [attr]
     * @param {object} [options]
     */
    constructor ( attr, options ) {
      super( attr, options );
  
      //eventsLoggerを有効化
      this.debugEvents( 'CollectionsVariables' );
  
      //noinspection JSUnusedGlobalSymbols
      /**
       * 永続先はlocalStorage、名前はdirPickerTemplatesCollection
       */
      this.localStorage = new BackboneLocalStorage( "dirPickerVariablesCollection" );
  
      /**
       *
       * @type {DirPickerVariable}
       */
      this.model = VariableModel;
  
      //noinspection JSUnusedGlobalSymbols
      /**
       *
       * @type {string}
       */
      this.comparator = 'sort';
    }
  }
  
  const dirPickerVariablesCollection = new DirPickerVariables();
  dirPickerVariablesCollection.fetch();
  export default dirPickerVariablesCollection;
  
subject: Refactor to ES6