Extjs I18n (Keys & Translations loaded from remote endpoint)

I18n.js

Ext.define('App.common.locale.I18n', {
    extend: 'Ext.Base',
    singleton: true,
    alternateClassName: ['I18n'],
    requires: [
        'App.store.locale.Translations', // in memory store to keep translations
        'App.api.config.Endpoints', // config file with endpoint information        
    ],
    initLocale: function (language) {        
        // STEP 1. find which language to load
        var pageParameters = Ext.urlDecode(window.location.search.substring(1));
        if (language) {
            this.locale = language;
            localStorage.setItem('userLanguage', language);
        } else if (pageParameters.lang && (pageParameters.lang === 'en' || pageParameters.lang === 'de' || pageParameters.lang === 'fr' || pageParameters.lang === 'it')) {
            // check in url
            localStorage.setItem('userLanguage', pageParameters.lang);
            this.locale = pageParameters.lang;
        } else {
            // check in localStorage
            var storedLocale = localStorage.getItem('userLanguage');
            this.locale = storedLocale ? storedLocale : 'en';
        }

        // STEP 2. Load translations
        // initialize translations from remote endpoint based on the language

        var translationStore = Ext.getStore('Translations');
        translationStore = translationStore || Ext.create('App.store.locale.Translations');        
        var translations = this.doGetSynchronous(this.locale);                
        translationStore.setProxy({ type: "memory", data: translations }).load();
        this.initialized = true;
    },
    get: function (key) {
        if (!this.initialized) {
            this.initLocale();
        }
        if (!key) {
            return '';
        }
        var store = Ext.getStore('Translations'),
            record = null;
        record = store.findRecord('key', key);
        if (record) {
            return record.get('value');
        } else {
            console.warn('No translation found for key ' + key);
            return key;
        }
    },
    locale: null,
    initialized: false,
    changeLanguage: function (language) {
        var newURL = window.location.pathname;
        // clean URL
        window.history.pushState("App", "App", newURL);
        this.initLocale(language);
        window.location.reload();
    },
    doGetSynchronous: function (language) {
        var response = null;
        Ext.Ajax.request({
            url: Endpoints.getUrl(Endpoints.urls.translations) + '/' + language,
            async: false,
            success: function (data) {
                var data = data || {};
                response = Ext.decode(data.responseText, true);
            },
            failure: function (error) {
                response = error;
            }
        });
        return response;
    }
});

Login.js

Ext.define('App.view.authentication.Login', {
    extend: 'Ext.container.Container',
    xtype: 'login-view',
    items : [
        {
            xtype: 'formpanel',
            title : I18n.get('Login.Title.Text')
        }
      ]
});

sample_data.json

[
    {
        "lang": "en",
        "key": "Login.Title.Text",
        "value" : "Welcome to your Account"
    }
]

Translations.js

Ext.define('App.store.locale.Translations', {
    extend: 'Ext.data.Store',
    alias: 'store.translations',
    storeId : 'Translations',
    fields: [ 'lang', 'key', 'value'],
    proxy: {
        type: 'memory',        
        reader: {
            type: 'json'
        }
    }
});