TypeScript for Titanium Mobile test application

app.js

var MyTabGroup = (function () {
    function MyTabGroup() {
        this.tabGroup = Ti.UI.createTabGroup();
    }
    MyTabGroup.prototype.appendTab = function (params) {
        for(var i = 0, l = params.length; i < l; i++) {
            this.tabGroup.addTab(Ti.UI.createTab(params[i]));
        }
    };
    MyTabGroup.prototype.open = function () {
        this.tabGroup.setActiveTab(0);
        this.tabGroup.open();
    };
    return MyTabGroup;
})();
var tabGroup = new MyTabGroup();
var win = Ti.UI.createWindow({
    title: "First TypeScript",
    backgroundColor: "#FFFFFF",
    tabBarHidden: true
});
win.add(Ti.UI.createLabel({
    text: "First TypeScript Apps for Ti!",
    color: "#666666"
}));
tabGroup.appendTab([
    {
        title: "First TypeScript",
        window: win
    }
]);
tabGroup.open();

app.ts

class MyTabGroup {
    constructor() {
        this.tabGroup = Ti.UI.createTabGroup();
    }
    appendTab(params) {
        for (var i = 0, l = params.length; i < l; i++) {
            this.tabGroup.addTab(Ti.UI.createTab(params[i]));
        }
    }
    open() {
        this.tabGroup.setActiveTab(0);
        this.tabGroup.open();
    }
}

var tabGroup = new MyTabGroup();
var win = Ti.UI.createWindow({
    title: "First TypeScript",
    backgroundColor: "#FFFFFF",
    tabBarHidden: true
});
win.add(Ti.UI.createLabel({
    text: "First TypeScript Apps for Ti!",
    color: "#666666"
}))
tabGroup.appendTab([{
    title: "First TypeScript",
    window: win
}]);
tabGroup.open();