How do I receive and use a JSON object on the client-side from the server (Node JS and Express)?

I am trying to do something seemingly very simple but I'm having trouble working it out. Users can submit some text using a HTML form with POST method. This is then sent off to an API for processing, and returns with a JSON object. I then just want the app.js file to send this JSON object back so I can play around with it using JQuery. Here is the .post method in my app.js

app.post('/', function(req, res){
 console.log("starting app.post");

  // See User Modeling API docs. Path to profile analysis is /api/v2/profile
  // remove the last / from service_url if exist
  var parts = url.parse(service_url.replace(/\/$/,''));

  var profile_options = { host: parts.hostname,
    port: parts.port,
    path: parts.pathname + "/api/v2/profile",
    method: 'POST',
    headers: {
      'Content-Type'  :'application/json',
      'Authorization' :  auth }
    };

  // create a profile request with the text and the https options and call it
  create_profile_request(profile_options,req.body.content)(function(error,profile_string) {
    if (error) {res.render('home.html',{'error': error.message});
                    console.log("errormessage: "+error.message);
  }
else {
  // parse the profile and format it
  var profile_json = JSON.parse(profile_string);
  var flat_traits = flatten.flat(profile_json.tree);      
  // Extend the profile options and change the request path to get the visualization
  var fileName="file 1"; //this will eventually be imported automatically
  //console.log(flat_traits);     
  var scoreObject={"title":fileName, "percentage":functions.matchPercentage(flat_traits)}
  res.send(scoreObject); //this is what I assume should send this back client-side      
      });
    }
  });
});

So I presume res.send is what passes the data across to the client-side, but then how do I receive the data on the client-side? This is my attempt at the JScript:

$.getJSON('/').done(function(data){
$('#resultsList').append('<li data-icon="arrow-r" data-iconpos="right" id="'+
        data.title+'">  <a href="#breakdownDialog"> <div id="cvResults"><h3>'+
        data.title+'</h3>   <span>'+data.percentage+
        '%</span></div></a><div id="output"></div></li>');
console.log(data.title+data.percentage);
}
});

I want to take some of the values from the JSON object and put them in a list on the existing HTML page. At the moment this just takes me to a different blank page that says Undefined. How should I grab the JSON data from the server?