Illustrator Scripting :: How To Convert File To JPEG

I am using following code to convert AI file to JPEG
 
exportFileToJPEG('~/Desktop/Harsh/1.jpg');
 
function exportFileToJPEG (dest) {
if ( app.documents.length > 0 ) {
var exportOptions = new ExportOptionsJPEG();
var type = ExportType.JPEG;
var fileSpec = new File(dest);

[Code]...
 
but ir crope the document to the size of the image and resize the ArtBoard to the size of Image.
 
I want to convert the Existing ArtBoard Area only , i dont want to crope the image.