Scripts Don't Move Opacity Masks

The version I'm working in is CC 2015.2.1. I am working with a vector object as the opacity mask over a vector object.

There are some great ideas here on how to work around it and using the move dialog seems like it would be the best workaround.
I was able to solve it another way. My final goal was to align the "art" with a "cut line". Finding that I could call actions with the script I did the following. It gathers the "cut lines" and finds the "art". Then, because you cannot select a key object for aligning with a script it copies the cut line and makes another in the equal but opposite direction of the art so that when it aligns, it aligns to the original cut line. This script allows you to have multiple cut lines and place the art in them.

var selectedItems = app.activeDocument.selection;

var cutLines = [];

var artItem;

for (var i = 0; i<selectedItems.length; i++){

    if (selectedItems.layer.name == 'DRT copy'){

        cutLines.push(selectedItems)

    }else{

        artItem = selectedItems;

    }

    selectedItems.selected = false;

}

for (var e = 0; e<cutLines.length; e++){

    var cLeft = cutLines.left;

    var cTop = cutLines.top;

    cutLines.selected = true;

    var offsetLeft = cLeft - artItem.pageItems[0].left;

    var offsetTop = cTop - artItem.pageItems[0].top;

    app.copy();

    app.paste()

    var offsetCut = app.activeDocument.selection[0];

    offsetCut.left = cLeft + offsetLeft;

    offsetCut.top = cTop + offsetTop;

    offsetCut.selected = false;

    artItem.selected = true;

    //app.doScript('Align Vertical', 'DevActions');

    app.copy();

    offsetCut.selected = true;

    cutLines.selected = true;

    app.doScript('Lock Pattern', 'DevActions');

     app.doScript('Align Horizontal', 'DevActions');

    app.doScript('Align Vertical', 'DevActions');

    app.doScript('Align Horizontal', 'DevActions');

    app.doScript('Align Vertical', 'DevActions');

    offsetCut.remove();

    artItem.selected = false;

    cutLines.selected = false;

    app.paste();

    artItem = app.activeDocument.selection[0];

    artItem.selected = false;

    if(e+1 == cutLines.length){

        artItem.selected = true;

        if(confirm('Are you done setting this peice?')){

            artItem.remove();

        }

    }

}

Always like JET's detailed explanation.

A dirty workaround can be like this:

var activeDoc = app.activeDocument;
var selectedItem = activeDoc.selection[0];
var gb = selectedItem.geometricBounds;
var cx = gb[0] + (gb[2] - gb[0]) / 2;
var cy = gb[1] + (gb[3] - gb[1]) / 2;
activeDoc.views[0].centerPoint = [cx, cy];
app.cut();
activeDoc.views[0].centerPoint = [cx - 10, cy - 10];
app.paste();

Moving to Illustrator Scripting​ for further help.

Always state what version you are using. You say you are dealing with an Opacity Mask, but only see a Compound Shape in the data browser. So you also need to clearly state exactly what kind of construct you have created. Have you used a vector path as an Opacity Mask on a Compound Shape?

Assuming CS6:

A search of the CS6 Javascript Reference for "Opacity Mask" or "Compound Shape" returns no ocurrences. So that implies that the scripting engine simply does not support those kind of objects. So boil the problem down to its essence and do a little testing to figure out what the scripting engine is "thinking."

1. New document.
2. Create a single closed path.
3. Create a filled rectangle overlapping it.
4. Select both.
5. Transparency palette: Make Mask.

6. Select the resulting object. Note what kind of object is selected in the Layers palette. To the program, it's listed as a Path, not an "Opacity Mask Group" or any other special construct.

If you add an alert(selectedItem.itemtype) to your script, when you run the script you will see what kind of object the scripting engine considers your seletedItem to be. In the above scenario, the itemtype for selectedItem is a "PathItem".

Dismissing the alert and letting the script complete, the PathItem moves, but its Opacity Mask does not.

7. Transparency palette: Release the mask.
8. Pathfinder palette: AltClick one of the ShapeModes buttons.
9. Note what kind of object is selected in the Layers palette. To the program, it's listed as a Compound Shape.

10. Run the script. The alert will tell you that the itemtype of selectedItem is "PluginItem".

Dismissing the alert and letting the script complete, the whole Compound Shape moves, including all its subpaths, so its effective "mask" moves with it.

If you add an alert(pageItems.length) to your script, you will see how many objects are considered to be in the document. In both scenarios, the count will be 1.

If you add an alert(pathItems.length) to your script, you will see how many paths are considered to be in the document. In the first scenario, there will be 1. (So the scripting engine does not include the path that was used as an Opacity Mask to be among its pathItems.) In the second scenario, the alert will return 0. So the scripting engine does not consider the elements of a the PluginItem to be pathItems. It treats the PluginItem as a kind of "foreign object."

So I don't see this as a bug. The Javascript model does not cover every feature, object, and command in the program.

So in the first scenario, the path which has an opacity mask applied is considered a path, and the Javascript engine references just the path and moves just the path. It doesn't "know anything about" an Opacity Mask. This kind of makes sense, because an Opacity Mask does not have to be just one single path. It can be pretty much anything; paths, raster images, live text. It can even be a group including all of those kinds of objects. Apply such a Group to a single path as an Opacity Mask, and the Layers palette will still list the construct as a path, and the Javascript engine will still address just the pathItem.

In the second scenario, it's clear that Compound Shapes created by the Pathfinder palette are constructs created by a plugin (an external program). So it also makes sense in that it is treated as a whole object, much like a placed external EPS or other foreign object.

JET