Copy Layer Mask

Question

As the subject suggests; I'm trying to find a way to copy a layer mask from one group to another.  I've looked around the web, but all I seem to find is a bunch of listener script that makes no sense, making it nearly impossible to get it to work for what I need.  I messed around with a layer script I have to copy layers between documents, but it doesn't seem to work the way I'd expect when trying to set it up for layer masks.  Anyway, the code I use for the layers is below.
                        var theCopyLayer = copyDoc.layers.getByName("Background");
                        var theCopiedLayer = theCopyLayer.duplicate(originalDoc.layerSets.getByName("stone").layers.getByName("mask"), ElementPlacement.PLACEBEFORE);
The layer mask I need is in the same document on a group; so the document switch isn't necessary.  Does anyone know of a way similar to this that would work for layer masks?  Or is the listener script the only option currently available?  Thanks!
dgolberg

Answer 1

but all I seem to find is a bunch of listener script that makes no sense
It may seem like it makes no sense, but that may not be easy to judge.
This function should work if you enter the (unique) name of the group the Layer Mask of which you want to duplicate onto the app.activeDocument.activeLayer.
function duplicateLayerMask (originLayerName) {
// =======================================================
var idMk = charIDToTypeID( "Mk  " );
    var desc2 = new ActionDescriptor();
    var idNw = charIDToTypeID( "Nw  " );
    var idChnl = charIDToTypeID( "Chnl" );
    desc2.putClass( idNw, idChnl );
    var idAt = charIDToTypeID( "At  " );
        var ref1 = new ActionReference();
        var idChnl = charIDToTypeID( "Chnl" );
        var idChnl = charIDToTypeID( "Chnl" );
        var idMsk = charIDToTypeID( "Msk " );
        ref1.putEnumerated( idChnl, idChnl, idMsk );
        var idLyr = charIDToTypeID( "Lyr " );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref1.putEnumerated( idLyr, idOrdn, idTrgt );
    desc2.putReference( idAt, ref1 );
    var idUsng = charIDToTypeID( "Usng" );
        var ref2 = new ActionReference();
        var idChnl = charIDToTypeID( "Chnl" );
        var idChnl = charIDToTypeID( "Chnl" );
        var idMsk = charIDToTypeID( "Msk " );
        ref2.putEnumerated( idChnl, idChnl, idMsk );
        var idLyr = charIDToTypeID( "Lyr " );
        ref2.putName( idLyr, originLayerName );
    desc2.putReference( idUsng, ref2 );
    var idDplc = charIDToTypeID( "Dplc" );
    desc2.putBoolean( idDplc, true );
executeAction( idMk, desc2, DialogModes.NO );