app.-properties in function erroring

Question

im quite a JS noob but trying to script my workflow. I modified a script to my needs, but suddenly the setting of app.-based properties doesnt work in a function anymore:

function myExport(Xquali, Xdpi, XAA, XSP, Xpath, BMcounter) {
  switch (Xquali) {
   case "Low": app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.LOW; break;
   case "Medium": app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.MEDIUM; break;
  case "High": app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.HIGH; break;
  case "Max": alert("?"); app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.MAXIMUM; alert("!");}

Theres obvious nothing wrong with this snippet, but all properties i try to change cancel my script – and i dont know how to find out why. Do you guys have any idea, why i can change eg jpgexport stuff outside my function, but not in there?

Answer 1

May i suggest a shorter snippet?

function myExport(Xquali) {
	if (!Xquali||!(typeof(Xquali)!=String)||!/low|medium|high|maximum/i.test(Xquali) ) return;
	app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality[Xquali.toUpperCase()];    
}

myExport("low"); //could be Low, LOW, low, loW,loW whatever
alert(app.jpegExportPreferences.jpegQuality);

FWIW