res.send and res.render calls

Question

I am trying to determine if i can call res.send(data) and then res.render('reports') simultaneously.

To explain further in detail, when i route to '/reports', first on my server side i making a REST call to an API which returns back json data. Now i want this json data to be accessed on the client, for which i am making an ajax call from my javascript. Hence the use of res.send(), but i also want to render the page in this call

So it looks like the following on my server side code

router.get('/reports', function(req,res){
     //Making the REST Call to get the json data
     //then
     res.send(json);
     res.render('reports');
});

Every time i hit the '/reports' on the browser, I see the json value instead of the page being rendered and my console throws an Error: Can't set headers after they are sent.

Answer 1

You could use content negotiation for that, where your AJAX request sets the Accept header to tell your Express server to return JSON instead of HTML:

router.get('/reports', function(req,res) {
  ...
  if (req.accepts('json')) {
    return res.send(theData);
  } else {
    return res.render('reports', ...);
  };
});

Alternatively, you can check if the request was made with an AJAX call using req.xhr (although that's not 100% failsafe).