Using:
var doc = new PDFDocument();
doc.pipe(res);
doc.text('Add content here');
doc.end();
within an Express GET route I'm able to navigate in the browser and view the PDF. Once viewed it can be saved or printed. 
That's good, but what I need is for the PDF to automatically download. The application will send a PUT to Express. From the one PUT, is it possible to also auto-download the PDF?  Angular needs a 200 response to return control to Angular and the user, but the PDF also needs to be downloaded.  
I've tried res.end(new Buffer(doc), 'binary), res.send(new Buffer(doc, 'binary')), etc, but can't get the PDF to download.  If I can't return a 200 and download the PDF from a PUT then my fallback is to PUT and once that returns do a window.open to the GET route to view the PDF. Kind of hacky, so  I would really prefer a download.
Options?
