The prop is not being passed into the response?

'use strict'; //this helps writer better code 

var express = require("express");
var app = express();
var routes = require("./routes"); //require routes from routes.js

var jsonParser = require("body-parser").json; //this will return middleware that we can add tp our app
var logger = require("morgan");


/*connect morgan to the app, passing in dev to our logger function
this will configure the middleware to give us colorful status codes for ous APIS responses*/
app.use(logger("dev")); 

/*when the app receives a request, this middleware will parse
the request's body as json and make it accessible from the req.body's property */
app.use(jsonParser()); 

//we want the router to kick in only when any route starts with /questions
app.use("/questions", routes);

// catch 404 and forward to error handler
app.use(function(req, res, next){
    var err = new Error("Not Found"); //use js native error constructor to create a new error object
    err.status = 404;
    next(err); //put err inside next(), this lets express know that there's been an error and pass it to the error handler below
});

// Error Handler

app.use(function(err, req, res, next){ //error handlers have 4 parameters, the 1st param is an error object
    res.status(err.status || 500); //if err object has a status property, set it to the HTTP status, if the err status is undefined use 500 status code 
    res.json({ //err is sent to client as json
        error: {
            message: err.message
        }
    });
});
//set up port
var port = process.env.PORT || 3000;
//set up server
app.listen(port, function(){ //provide a function that displays message 
    console.log("Express server is listening on port", port);
});

'use strict';

var express = require("express");
var router = express.Router(); //we'll pass the router object into the main app by exporting at the end of this file

// GET /questions
// Route for questions collection
router.get("/", function(req, res){
    res.json({response: "You sent me a GET request"});
});

// POST /questions
// Route for creating questions
router.post("/", function(req, res){
    res.json({
        response: "You sent me a POST request",
        body: req.body
    });
});

// GET /questions/:id
// Route for specific questions
router.get("/:qID", function(req, res){
    res.json({
        response: "You sent me a GET request for ID " + req.params.qID
    });
});

// POST /questions/:id/answers
// Route for creating an answer
router.post("/:qID/answers", function(req, res){
    res.json({
        response: "You sent me a POST request to /answers",
        questionId: req.params.qID,
        body: req.body
    });
});

// PUT /questions/:qID/answers/:aID
// Edit a specific answer
router.put("/:qID/answers/:aID", function(req, res){
    res.json({
        response: "You sent me a PUT request to /answers",
        questionId: req.params.qID,
        answerId: req.params.aID,
        body: req.body
    });
});

// DELETE /questions/:qID/answers/:aID
// Delete a specific answer
router.delete("/:qID/answers/:aID", function(req, res){
    res.json({
        response: "You sent me a DELETE request to /answers",
        questionId: req.params.qID,
        answerId: req.params.aID
    });
});

// POST /questions/:qID/answers/:aID/vote-up
// POST /questions/:qID/answers/:aID/vote-down
// Vote on a specific answer
router.post("/:qID/answers/:aID/vote-:dir", function(req, res, next){
        if(req.params.dir.search(/^(up|down)$/) === -1) { //the expression will reject any values that are not up or down
            var err = new Error("Not Found"); //create new error if url values are not up or down
            err.status = 404;
            next(err);
        } else { //if the url contents are valid, call next() normally
            next();
        }
    }, function(req, res){
    res.json({
        response: "You sent me a POST request to /vote-" + req.params.dir,
        questionId: req.params.qID,
        answerId: req.params.aID,
        vote: req.params.dir
    });
});
//export  router variable so we can access it in
module.exports = router;