gistfile1.js

    updateVersionDropdown : function() {
        var versionsByLang = {},
            getLang = function (v) { return v.get('lang'); },
            selectorHTML;

        // Loop through the version model
        _.each(
            // Group versions by language, 
            // and sort the lang keys alphabetically.
            _.groupBy(_.sortBy(this._versions.models, getLang), getLang), 

            // Sort the versions within each lang group
            // and populate the new version object
            function(version, lang) {
                versionsByLang[lang] = _.sortBy(version, function(ver) {
                    return ver.get('display_abbreviation');
                });
            });      
        
        selectorHTML = ABS.jst.PassageVersionSelector({
            versionsByLang: versionsByLang,
            current:        this.collection.primaryModel.get('version')
        });

        this.$('div.change-version').empty().append(selectorHTML);
    }