Demonstrates what using CommonJS can look like for a standard tab group on iOS or Android using Appcelerator Titanium. Note that I recommend placing the "ui-" stuff in a "ui" directory, but Gists don't let me do subdirectories.

app.js

var tabGroup = Ti.UI.createTabGroup({
    backgroundColor: '#fff'
});

tabGroup.addTab(Ti.UI.createTab({
    title: 'Tab 1',
    window: require('ui-win1').createWindow(),
    icon: 'images/tab-1.png'
}));

tabGroup.addTab(Ti.UI.createTab({
    title: 'Tab 2',
    window: require('ui-win2').createWindow(),
    icon: 'images/tab-2.png'
}));

require('push').startListening();

tabGroup.open();

push.js

exports.startListening = function() {
    // do your registerForPushNotifications
    // when you do get a push, you can Ti.App.fireEvent if there is UI you want to update.
};

ui-label.js

exports.createView = function (args) {
    if (!args) args = {};
    if (!args.color) args.color = 'blue';

    return Ti.UI.createLabel(args);
};

ui-win1.js

exports.createWindow = function () {
    var win = Ti.UI.createWindow({
        backgroundColor: '#fff'
    });
    win.add(require('ui-label').createView({
        text: 'This is Win 1'
    }));
    return win;
};

ui-win2.js

exports.createWindow = function () {
    var win = Ti.UI.createWindow({
        backgroundColor: '#fff'
    });
    win.add(require('ui-label').createView({
        text: 'This is Win 2'
    }));
    return win;
};