Custom error response code and message

[mikkelfish]

Hello, right now I see that response codes for errors are hardcoded to the route. This can cause confusion when there is an internal error because the client thinks it is a bad request.

In addition, the error message does not serialize correctly when passing an Error object, which several other middlewares require.

I have locally hacked

exports.respondOrErr = function(res, errStatusCode, err, statusCode, content) {
  if (err) {
    exports.respond(res, err.statusCode || errStatusCode, err.message || err);
  } else {
    exports.respond(res, statusCode, content);
  }
};

and then am passing an Error like so

var error = new Error(err);
error.statusCode = 500;
next(error); 

Is this satisfactory/best practice? Didn't feel like making a pull request for such a minor change without knowing that the pattern was acceptable.

Thanks