Error: write after end I get this error emitted after trying to add response.end() like in the video

var Profile = require("./profile.js");
var renderer = require("./renderer.js");


// handles the http  route GET / POST i e home


function home(request,response) {





    //if the url = "/ && GET " 

  if (request.url === "/") {
        //show the search field
    response.writeHead(200, {'Content-Type': 'text/plain'});    
    renderer.view("header" , {} , response);
    renderer.view("search" , {} , response);
    renderer.view("footer" , {} , response);
    response.end();

  }
    //if the url = "// && POST " 
        //redirect to the username
}


//handles the http route get / username i.e /jonathanleo

function user(request,response) {

  var username = request.url.replace("/", "");

//if the url = "//..."

  if (username.length > 0 ) {


    response.writeHead(200, {'Content-Type': 'text/plain'});    
    renderer.view("header" , {} , response);
    response.end();

//get the JSOn from treehouse  

      var studentProfile = new Profile(username);


//on end
        studentProfile.on("end", function(profileJSON){

//show the profile

          //store the values which we need

          var values = {
            avatarUrl: profileJSON.gravatar_url ,
            username: profileJSON.profile_name ,
            badges: profileJSON.badges.length ,
            javascriptPoints: profileJSON.points.JavaScript
          }
          //simple response
    renderer.view("profile" , values , response);
    renderer.view("footer" , {} , response);
    response.end();
        });



//on error
        studentProfile.on("error", function(error) {

//show the error

          renderer.view("error" , {errorMessage: error.message} , response);
          renderer.view("search" , {} , response);
          renderer.view("footer" , {} , response);
          response.end();
       });


     }
  };




module.exports.home = home;
module.exports.user = user;