5 Code Signals

2.js

app.get('/api/friends/:_id',function(req,res,next){
        Friends.findOne({ '_id': req.params._id , user_id: req.currentUser.id})
          .exec(function (err, friend_list) {
            if (err) {
                return next(err);
            }
            if (friend_list) {
                res.send(friend_list);
            } else {
                return next(new NotFound('Could not find any such Friend'));
            }
        });
    });