Error handling for Node.js

node-error-handling.js

var NotFoundError = module.exports.NotFoundError = function (message) {
  this.name = 'NotFoundError: ' + message;
  Error.call(this, message);
  Error.captureStackTrace(this, arguments.callee);
};
NotFoundError.prototype.__proto__ = Error.prototype;
var UnauthorizedError = module.exports.UnauthorizedError = function (message) {
  this.name = 'UnauthorizedError: ' + message;
  Error.call(this, message);
  Error.captureStackTrace(this, arguments.callee);
};
UnauthorizedError.prototype.__proto__ = Error.prototype;
var BadRequestError = module.exports.BadRequestError = function (message) {
  this.name = 'BadRequestError: ' + message;
  Error.call(this, message);
  Error.captureStackTrace(this, arguments.callee);
};
BadRequestError.prototype.__proto__ = Error.prototype;

app.error(function (err, req, res, next) {
  console.log(err.message || 'Error: ocur unknown error');
  console.log(err.stack);
  var error = new mongodb.errors(
    { stack: middle.sanitize(err.stack), message: middle.sanitize(err.message) });
  error.save(middle.log());
  if (err instanceof BadRequestError) {
    res.local('title', 'Bad Request');
    res.local('status', 400);
  } else if (err instanceof UnauthorizedError) {
    res.local('title', 'Unauthorized');
    res.local('status', 401);
  } else {
    res.local('title', 'Not found');
    res.local('status', 404);
  }
  res.render('error', {
    url: req.url,
    error: error    });
});
app.use(function (req, res, next) {
  var message = 'NotFoundError: cannot find ' + req.url;
  console.log(message);
  var error = new mongodb.errors(
    { message: middle.sanitize(message) });
  error.save(middle.log());
  res.render('error', {
    title: 'Not found',
    status: 404,
    url: req.url,
    error: false
  });
});