[Titanium] How to detect window orientation (portrait vs landscape) at start-up

Titanium provides a simple way to detect window orientation, Titanium.UI.Window.orientation, but it seems to initialize late. In an application I’m developing, I needed to check the window orientation right at start-up, more specifically I used this:
if(Titanium.UI.Window.orientation==Titanium.UI.PORTRAIT) {stuff}
but this didn’t seem to work.

Running a simple
console.log(Titanium.UI.Window.orientation)
revealed that the variable sadly is undefined at that stage (TBH, I didn’t check if it was defined later since that’s not where I need it).

So I made a custom function, based on window size, which turns out to be defined early enough for me. Here is the function, quite obvious, really:
var isPortrait = function(){
return (Ti.Platform.displayCaps.platformHeight > Ti.Platform.displayCaps.platformWidth);
};

Then just call it with isPortrait() to get a boolean with value true if the window is oriented in portrait and false if it’s oriented in landscape.

Note that I only needed to make the difference between portrait and landscape, I don’t really have an idea to make the difference between properly oriented and upside-down portrait, or between left of right landscape, as the Titanium.UI.Window.orientation property offers (its possible values are: Titanium.UI.LANDSCAPE_LEFT, Titanium.UI.LANDSCAPE_RIGHT, Titanium.UI.PORTRAIT and Titanium.UI.UPSIDE_PORTRAIT)