Enum on Sencha Touch (ExtJS as well?)

EnumBase.js

/**
 * @abstract
 * @class MyApp.EnumBase
 */
Ext.define('MyApp.EnumBase', {

    inheritableStatics: {
        /**
         * @return {Array.<MyApp.EnumBase>}
         */
        values: function () {
            return this._items.map(function (item) {
                return Ext.isString(item) ? this[item] :
                       Ext.isObject(item) ? this[item.name] : null;
            }, this);
        },

        /**
         * @private
         * @type {Array.<Object|string>} if use Objects, make sure they have `name` propertes
         */
        _items: [],

        /**
         * Must be called in override classes when right after they're defined
         * @protected
         */
        _initializeEnum: function () {
            Ext.Array.each(this._items, function (item, index) {
                if (Ext.isString(item)) {
                    this[item] = new this({index: index});
                } else if (Ext.isObject(item) && item !== null) {
                    var tmpItem = Ext.clone(item);

                    delete tmpItem.name;

                    this[item.name] = new this(Ext.apply(tmpItem, {index: index}));
                } else {
                    throw new Error('Enum item should be given as either an Object or a string');
                }
            }, this);

            this.prototype.constructor = function () {
                throw new Error('Items of enum can be generated only on declaration');
            };
        }
    },

    config: {
        /**
         * @cfg {number}
         */
        index: -1

    },

    constructor: function (config) {
        this.initConfig(config);
    }

});

Season.js

/**
 * @class MyApp.Season
 */
Ext.define('MyApp.Season', {
    extend: 'MyApp.EnumBase',

    requires: ['MyApp.EnumBase'],

    statics: {
        /**
         * @private
         * @type {Array.<Object|string>}
         */
        _items: [{
            name   : 'SPRING',
            bestFor: 'hiking'
        }, {
            name   : 'SUMMER',
            bestFor: 'swimming'
        }, {
            name   : 'AUTUMN',
            bestFor: 'playing tennis'
        }, {
            name   : 'WINTER',
            bestFor: 'skiing'
        }]
    },

    config: {
        /**
         * @cfg {string}
         */
        bestFor: ''
    }

}, function () {

    // Any ideas to do it in the super class?
    this._initializeEnum();

});

// Test
MyApp.Season.values()                            // => [Class, Class, Class, Class]
MyApp.Season.values()[3] === MyApp.Season.WINTER // => true
MyApp.Season.WINTER instanceof MyApp.Season      // => true
MyApp.Season.WINTER.getBestFor()                 // => "skiing"
MyApp.Season.WINTER.getIndex()                   // => 3
Ext.create('MyApp.Season', {name: 'foo'})        // => Uncaught Error: Items of enum can be generated only on declaration