Relative Stacking order of Sub Layers and items

Question

I want to get the items in a layer sorted in their stacking order (including any sub-layers).
For example:
Layer 1
   item A
   Layer 1a
   Group B
   item C
In the example above, I would get back an array like this:
[item A, layer 1a, Group B, item C]
Of course, you'd think this is a simple enough thing given that zOrderPosition is freely available:
function getChildrenInStackingOrder(layer){
    var sublayers=layer.layers;
    var pageItems=layer.pageItems;
    var result=new Array ();
    var size=sublayers.length+pageItems.length;
    for(var i=0;i<sublayers.length;i++){
       result[sublayers[i].zOrderPosition]=sublayers[i];  <<<----------- ERROR
    for(var i=0;i<pageItems.length;i++){
       result[pageItems[i].zOrderPosition]=pageItems[i];
    return result;
My problem is that AI CS4 throws up at the line marked above with a message "Internal Error 1200". I'm guessing that it's illegal to get the zOrderPosition of a sublayer.  Any thoughts?
Anurag.
PS. Do any Adobe engineers read this forum at all? Seems like there's a lot of internal documentation that could help in answering some of our questions.

Answer 1

This is a BUG.  Bugs exist in any software. But when a company allows its users to waste hours and hours trying to figure out what they're doing wrong, only to find it's a bug that Adobe didn't bother to document prominently in their user guides, it borders on cruel. And it will continue to happen to others.
Illustrator's scripting documentation clearly says that zOrderPosition is available (read-only, which is fine) for all PageItem and Layer objects. The fact that it is relative to the parent group or layer is totally OK; it's good, in fact. Or it would be, if it wasn't useless because it is broken. "Internal Error" ? ngngn..
Some of the replies here point to possible workarounds using Document.pageItems, it's unforgiveable that such a workaround is necessary, but here is another, similar trick. It relies on an interesting (undocumented) aspect of how selections behave: If you select a bunch of objects in any order and then iterate through Document.selection, it turns out that the objects in the selection array have been sorted into proper z-order for you.
var doc = app.activeDocument;
var layer = doc.activeLayer; // select your parent layer before running this
// Convert a collection to a regular JS Array, so we can use concat()
function toArray(coll) {
    var arr = [];
    for (var i = 0; i < coll.length; ++i) {
        arr.push(coll[i]);
    return arr;
// Get all the objects in a layer and its descendent layers
function getAllPageItems(layer) {
     var items = toArray(layer.pageItems);
     for each (var sublayer in toArray(layer.layers)) {
          items = items.concat(getAllPageItems(sublayer));
     return items;
var items = getAllPageItems(layer);
// Some items here will not be in z-order.
for each (var item in items) {
     $.writeln(item);
$.writeln("---------------------------");
// Select everything in the active layer:
doc.selection = items;
//Notice that the objects have been resorted into z-order in doc.selection:
for each (item in doc.selection) {
     $.writeln(item);
Of course if you want to preserve the original layers without flattening, you'll have to do some additional, ridiculous stuff. But, hope this helps someone.
Anyone out there who looks at this and thinks "What an idiot, doesn't this guy know you can just do 'x' .." PLEASE correct me, and be as disparaging as you want. I will still thank you.