var _dokA = app.documents[0]; 
var parentfolder = _dokA.filePath; 
$.writeln(parentfolder); 
var _dokA_name = _dokA.name; 
var _nameA_teil = _dokA_name.slice(0,-5); 
var _dokB_name = _nameA_teil + "_Kopie.indd"; 
var _dokB_pfad = _dokA.filePath+"/"+_dokB_name; 
$.writeln (_dokB_pfad); 
var _dokB = _dokA.SaveAs(_dokB_pfad); 

// FileName: WpsSaveAs.jsx 
//  © 2020 by Werner Perplies, EDV-Anwendungsberatung 
// http://www.weepee.de, email: werner.perplies@weepee.de 
// created: Thu Feb 06 2020 06:44:16 GMT+0100 
// [end of header] 
#target indesign-8.0 
#targetengine "WpsSaveAs" 
alert(main()); 
 
/*String*/function main(){ 
    try{ 
        var /*String*/resultMsg = "",  
            /*Document*/doc = app.documents[0],  
            /*String*/name = doc.name.split(".")[0],  
            /*String*/folder = ""; 
            if (doc.saved){ 
                folder = doc.filePath; 
                doc =doc.save(File(folder + "/" + name + "_Kopie-indd")); 
                resultMsg = "Dokument wurde als \n\""  + doc.fullName + "\"\ngespeichert.!"; 
            } 
            else{ 
                resultMsg = "Fehler: Das Dokument wurde noch nicht gespeichert"; 
            } 
    } 
    catch (error){ 
        resultMsg = "Fehler: "+ error.message + "\nFehlernummer: " + error.number + "\nin Zeile: " + error.line + "\n"; 
    } 
    return resultMsg; 
}