How to find selected Top group layers (layeSets), relative position

[siomosp]

Thi is my code to find selected Top group layers (layeSets),  relative position.
I am using it to avoid selecting document active layer using "getByName".

The number can be used at:

app.activeDocument.activeLayer = app.activeDocument.layerSets[2];

I hope it is usefull and correct, since i have almost none exprerience at scripting

( There are similar posts based on ActionManager I think, but I this code is easier to use)

var sel_name = app.activeDocument.activeLayer.name;
var c = -1;
for(var i = 0; i < app.activeDocument.layerSets.length; i++) {
  if(activeDocument.layerSets[i].typename == "LayerSet")
{c++} 
if (app.activeDocument.layerSets[c].name == sel_name) {
var layerset_index = i;
}
alert(layerset_index);

[Kukurykus]

aD = activeDocument, lSs = [].slice
.call(aD.layerSets); while(lSs.length) {
	if (lSs.pop() == aD.activeLayer) {
		alert(lSs.length); break
	}
}