Automatisatin of duplication layers

Like I wrote in your last thread, a layer doesn't have a duplicate method.

You have to go "the long way":

Create a new layer and duplicate all items from original layer to the new one.

// layers have no duplicate method - that's why 
// regards pixxxelschubser
var aDoc = app.activeDocument;
var dupLay = aDoc.layers.add();
dupLay.name = "Duplicat";
redraw();
var aLay = aDoc.layers.getByName("X"); // your existing layer name
var pI = aLay.pageItems;

for (k=pI.length-1; k>=0;k--) {
pI[k].duplicate(dupLay, ElementPlacement.PLACEATBEGINNING);
}

If that works for you

have fun

😉