gistfile1.js

    updateVersionDropdown : function() {
        var versionsByLang = {};

        // Loop through the version model
        _.each(
            // Group versions by language, 
            // and sort the lang keys alphabetically.
            _.groupBy(_.sortBy(this._versions.models, function (ver) {
                return ver.get('lang');
            }), function (ver) {
                return ver.get('lang');
            }), 
            // Sort the versions within each lang group
            // and populate the new object
            function(version, lang) {
                versionsByLang[lang] = _.sortBy(version, function(ver) {
                    return ver.get('display_abbreviation');
                });
            }
        );
        
        var selectorHTML = ABS.jst.PassageVersionSelector({
            versionsByLang: versionsByLang,
            current:        this.collection.primaryModel.get('version')
        });

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