Export adobe illustrator visible layers to png files with the same layer name structure (layers->sublayers becomes folder->subfolders)

ai.export.js

// Export Layers as PNG files  with original layer structure

var options = new ExportOptionsPNG24();

var doc = app.activeDocument;
$.writeln("trying to save");

var newdoc = app.documents.add(doc.documentColorSpace, doc.width, doc.height);
newdoc.artboards[0].artboardRect = doc.artboards[0].artboardRect;


saveSubLayers(doc, "");

newdoc.close(SaveOptions.DONOTSAVECHANGES);

function saveSubLayers(node, path){
    for (var i=0; i<node.layers.length; i++){
        var layer = node.layers[i];
        if (!layer.visible) 
                continue;
        if (layer.layers.length > 0){
             saveSubLayers(layer, path+"/"+layer.name);
        } else {
            saveLayer(layer, path);
        }        
    }
}


function saveLayer(layer, path){
    newdoc.layers[0].remove();
    var newlayer = newdoc.layers[0];
	for (var ii = layer.pageItems.length - 1; ii >= 0; ii--)
		layer.pageItems[ii].duplicate(newlayer, ElementPlacement.PLACEATBEGINNING);

	new Folder(doc.path + path).create();
	newdoc.exportFile(new File(doc.path + path + "/" + layer.name + ".png"), ExportType.PNG24, options);
}

How would this be edited to retain artboard sizes vs. snapping to the layers artwork dimensions?