Duplicate and separate linked smart objects.jsx

// https://gist.github.com/joonaspaakko/ace1ec3455b6959dc611

#target photoshop

// If there are any documents open, run the code...
// =================================================
if ( app.documents.length > 0 ) {

    // Used later on when the layers are duplicated back to the original document.
    // ===========================================================================
    var docName = app.activeDocument.name;

    // Script listener code - Duplicate active group to a new document.
    // =================================================================
    var idMk = charIDToTypeID( "Mk  " );
        var desc14 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
            var ref10 = new ActionReference();
            var idDcmn = charIDToTypeID( "Dcmn" );
            ref10.putClass( idDcmn );
        desc14.putReference( idnull, ref10 );
        var idUsng = charIDToTypeID( "Usng" );
            var ref11 = new ActionReference();
            var idLyr = charIDToTypeID( "Lyr " );
            var idOrdn = charIDToTypeID( "Ordn" );
            var idTrgt = charIDToTypeID( "Trgt" );
            ref11.putEnumerated( idLyr, idOrdn, idTrgt );
        desc14.putReference( idUsng, ref11 );
        var idVrsn = charIDToTypeID( "Vrsn" );
        desc14.putInteger( idVrsn, 5 );
    executeAction( idMk, desc14, DialogModes.NO );     

    // Script listener code - Select first layer ( not counting Background layer).
    // Just in case more than one layer was selected.
    // ===========================================================================
    var idslct = charIDToTypeID( "slct" );
        var desc76 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
            var ref33 = new ActionReference();
            var idLyr = charIDToTypeID( "Lyr " );
            ref33.putName( idLyr, app.activeDocument.layers[0].name );
        desc76.putReference( idnull, ref33 );
        var idMkVs = charIDToTypeID( "MkVs" );
        desc76.putBoolean( idMkVs, false );
    executeAction( idslct, desc76, DialogModes.NO );

    // Script listener code - Replace contents.
    // =====================================================================
    var idplacedLayerReplaceContents = stringIDToTypeID( "placedLayerReplaceContents" );
        var desc8 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
        desc8.putPath( idnull, new File( "~" ) );
    executeAction( idplacedLayerReplaceContents, desc8, DialogModes.ALL );

    // Script listener code - Select all layers again
    // =======================================================
    var idselectAllLayers = stringIDToTypeID( "selectAllLayers" );
        var desc125 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
            var ref59 = new ActionReference();
            var idLyr = charIDToTypeID( "Lyr " );
            var idOrdn = charIDToTypeID( "Ordn" );
            var idTrgt = charIDToTypeID( "Trgt" );
            ref59.putEnumerated( idLyr, idOrdn, idTrgt );
        desc125.putReference( idnull, ref59 );
    executeAction( idselectAllLayers, desc125, DialogModes.NO );

    // Script listener code - Duplicate active group to the prior document.
    // =====================================================================
    var idDplc = charIDToTypeID( "Dplc" );
        var desc16 = new ActionDescriptor();
        var idnull = charIDToTypeID( "null" );
            var ref13 = new ActionReference();
            var idLyr = charIDToTypeID( "Lyr " );
            var idOrdn = charIDToTypeID( "Ordn" );
            var idTrgt = charIDToTypeID( "Trgt" );
            ref13.putEnumerated( idLyr, idOrdn, idTrgt );
        desc16.putReference( idnull, ref13 );
        var idT = charIDToTypeID( "T   " );
            var ref14 = new ActionReference();
            var idDcmn = charIDToTypeID( "Dcmn" );
            ref14.putName( idDcmn, docName );
        desc16.putReference( idT, ref14 );
        var idVrsn = charIDToTypeID( "Vrsn" );
        desc16.putInteger( idVrsn, 5 );
    executeAction( idDplc, desc16, DialogModes.NO );

    // Closes the new document.
    // =======================================================
    app.activeDocument.close( SaveOptions.DONOTSAVECHANGES );

}