How to get the dimensions of multiple selected layers?

// edited
// 2025, use it at your own risk;
if (app.documents.length > 0) {
var originalRulerUnits = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;
var theLayers = collectSelectedLayersBounds ();
var x1 = theLayers[0][2][0];
var x2 = theLayers[0][2][2];
var y1 = theLayers[0][2][1];
var y2 = theLayers[0][2][3];
for (var m = 1; m < theLayers.length; m++) {
var x1 = Math.min(x1, theLayers[m][2][0]);
var x2 =  Math.max(x2, theLayers[m][2][2]);
var y1 =  Math.min(y1, theLayers[m][2][1]);
var y2 =  Math.max(y2, theLayers[m][2][3]);
};
alert ("selected layers\n"+(x2-x1)+"\n"+(y2-y1));
app.preferences.rulerUnits = originalRulerUnits;
};
////// collect bounds of selected layers //////
function collectSelectedLayersBounds () {
// set to pixels;
    var originalRulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;
// get selected layers;
    var selectedLayers = new Array;
    var ref = new ActionReference();
    ref.putEnumerated( charIDToTypeID("Dcmn"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
    var desc = executeActionGet(ref);
    if (desc.getBoolean(stringIDToTypeID("hasBackgroundLayer")) == true) {var theAdd =0}
    else {var theAdd = 1};
    if( desc.hasKey( stringIDToTypeID( 'targetLayers' ) ) ){
    desc = desc.getList( stringIDToTypeID( 'targetLayers' ));
    var c = desc.count;
    var selectedLayers = new Array();
    // run through selected layers;
    for(var i=0;i<c;i++){
    var theIndex = desc.getReference( i ).getIndex()+theAdd;
    // get id for solid color layers;
    try {
    var ref = new ActionReference();
    ref.putIndex( charIDToTypeID("Lyr "), theIndex ); 
    var layerDesc = executeActionGet(ref);
    var theName = layerDesc.getString(stringIDToTypeID('name'));
    var theIdentifier = layerDesc.getInteger(stringIDToTypeID ("layerID"));
    var theBounds = layerDesc.getObjectValue(stringIDToTypeID("bounds"));
    var theseBounds = [theBounds.getUnitDoubleValue(stringIDToTypeID("left")), theBounds.getUnitDoubleValue(stringIDToTypeID("top")), theBounds.getUnitDoubleValue(stringIDToTypeID("right")), theBounds.getUnitDoubleValue(stringIDToTypeID("bottom"))];
    selectedLayers.push([theName, theIdentifier, theseBounds]);
    //selectedLayers.push([theName, theseBounds[2] - theseBounds[0], theseBounds[3] - theseBounds[1]])
    } catch (e) {};
    };
    // if only one:
    }else{
    var ref = new ActionReference();
    ref.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
    var layerDesc = executeActionGet(ref);
    try {
    var theName = layerDesc.getString(stringIDToTypeID('name'));
    var theIdentifier = layerDesc.getInteger(stringIDToTypeID ("layerID"));
    var theBounds = layerDesc.getObjectValue(stringIDToTypeID("bounds"));
    var theseBounds = [theBounds.getUnitDoubleValue(stringIDToTypeID("left")), theBounds.getUnitDoubleValue(stringIDToTypeID("top")), theBounds.getUnitDoubleValue(stringIDToTypeID("right")), theBounds.getUnitDoubleValue(stringIDToTypeID("bottom"))];
    selectedLayers = [[theName, theIdentifier, theseBounds]]
    //selectedLayers = [[theName, theseBounds[2] - theseBounds[0], theseBounds[3] - theseBounds[1]]]
    } catch (e) {};
    };
// reset;
    app.preferences.rulerUnits = originalRulerUnits;
    return selectedLayers;
};