Test mask visibility in pscc 2014

Question

I have heard good comments about indesign scripting community.
It occurred to ask a Photoshop scripting question here given the good reputation of this community.
The photoshop document has a layer with a layer mask.
Using the extended script or javascript,
How would I test if the layer mask is visible or hidden?
Trying to create a script that toggles the visibility of a layer mask.
So far the script can call the showMask or hideMask functions independently.
The next step is to test for the mask visibility and call the corresponding function.
I believe this can be achieved with an if statement.
// if mask visible
     call hideMask()
// if mask not visible
     call showMask()
#target photoshop
//Make Photoshop the formost Application
app.bringToFront();
//Test for open document
if(app.documents.length > 0){
        //Select mask layer 255 fill
        var docRef = app.activeDocument;
        var layerRef=docRef.layers.getByName("255 fill");      //"Layer Name" 
        docRef.activeLayer=layerRef;
        // call showMask function
        //showMask ();
        // call hideMask function
        //hideMask ();
        //toggle mask visibility              
else {
    alert("No documents are open");
// FUNCTIONS
function showHideMask () {
    // showMask
    // =======================================================
    var idslct = charIDToTypeID( "slct" );
        var desc21 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
            var ref21 = new ActionReference();
            var idChnl = charIDToTypeID( "Chnl" );
            var idChnl = charIDToTypeID( "Chnl" );
            var idMsk = charIDToTypeID( "Msk " );
            ref21.putEnumerated( idChnl, idChnl, idMsk );
        desc21.putReference( idnull, ref21 );
        var idMkVs = charIDToTypeID( "MkVs" );
        desc21.putBoolean( idMkVs, true );
    executeAction( idslct, desc21, DialogModes.NO );
function hideMask () {
    // hideMask
    // =======================================================
        var idslct = charIDToTypeID( "slct" );
            var desc22 = new ActionDescriptor();
            var idnull = charIDToTypeID( "null" );
                var ref22 = new ActionReference();
                var idChnl = charIDToTypeID( "Chnl" );
                var idChnl = charIDToTypeID( "Chnl" );
                var idRGB = charIDToTypeID( "RGB " );
                ref22.putEnumerated( idChnl, idChnl, idRGB );
            desc22.putReference( idnull, ref22 );
            var idMkVs = charIDToTypeID( "MkVs" );
            desc22.putBoolean( idMkVs, false );
        executeAction( idslct, desc22, DialogModes.NO );

Answer 1

There have been a couple of threads on this and apparently people at Adobe are aware that the feature has been broken.
Re: I updated photoshop CC to 2014 version and the photomerge fuction does not work as the previous version, it is worse. When blending images it crops with nearly strait line, without considering image items. At the previous version croping was much more