Creating robust promise-based controllers with X-Error

X-Error Controller Example.js

var buildCtrl = function(promiseFn){
  return function(req, res) {
    promiseFn(req)
    .then(function(data){

      res.json(200, data);

    }, function(e){

      res.status(e.httpCode || 500)
         .send(e.httpResponse || 'Internal error');

    });
  };
};

// User API
var user = {
  find: function(req){
    return User.find(req.params.id)
    .then(function(user){
      if (!user) throw new XError(1000).hc(400).hr('User not found').d(req.params.id);
      return user;
    });
  },
  
  create: function(req){
    return User.create(req.body)
    .then(null, function(e){
      throw XError(1001, e).hc(400).hr('Unable to create user').d(req.body);
    });
  }
};

app.get('/user/:id', buildCtrl(user.find));
app.post('/user', buildCtrl(user.create));