Simple Photoshop script that renames selected layers

RenameLayers.jsx

#target photoshop

function main() {
    if (app.activeDocument == null) {
        alert("You should open some document to execute that script" + selectedLayers.length);
        return;        
    }
    
    selectedLayers = getSelectedLayers();
    if  (selectedLayers.length == 0) {
        alert("You should select at least one layer" + selectedLayers.length);
        return;
    }

    var newLayerName = prompt("Rename selected layers to:", selectedLayers[0].name);
    if  (newLayerName == null) return;

    for (var i=0; i<selectedLayers.length;i++) {
        selectedLayers[i].name = newLayerName;
    }
}
main();

// Get selected layers function from http://stackoverflow.com/a/37107154/3802890
function getSelectedLayers() {
  var resultLayers = new Array();
  try {
    var idGrp = stringIDToTypeID( "groupLayersEvent" );
    var descGrp = new ActionDescriptor();
    var refGrp = new ActionReference();
    refGrp.putEnumerated(charIDToTypeID( "Lyr " ),charIDToTypeID( "Ordn" ),charIDToTypeID( "Trgt" ));
    descGrp.putReference(charIDToTypeID( "null" ), refGrp );
    executeAction( idGrp, descGrp, DialogModes.NO );
    for (var ix=0;ix<app.activeDocument.activeLayer.layers.length;ix++) {
        resultLayers.push(app.activeDocument.activeLayer.layers[ix])
    }
    var id8 = charIDToTypeID( "slct" );
    var desc5 = new ActionDescriptor();
    var id9 = charIDToTypeID( "null" );
    var ref2 = new ActionReference();
    var id10 = charIDToTypeID( "HstS" );
    var id11 = charIDToTypeID( "Ordn" );
    var id12 = charIDToTypeID( "Prvs" );
    ref2.putEnumerated( id10, id11, id12 );
    desc5.putReference( id9, ref2 );
    executeAction( id8, desc5, DialogModes.NO );
    } catch (err) {
        // Ignore error
    }
    return resultLayers;
}