Send Node response to ember template

I just wrote my first function on my MEEN stack application. Its a basic file upload page that a user can upload a csv, this then triggers a function on post request to the route with node.

My question is when I am done processing with node I want to just send back a flash message that can then be rendered in the ember template, like 'Done Processed '+ x rows

I've tried res.send and res.json but it just renders the response to text in the browser, how can I push this data to the template on completion?