Passing object to node's Error class returns an unaccessible object

Question

I'm returning an Error object, to which I pass an object (instead of a simple message):

if (err) {
   return myCallback(new Error({
      error_code: 'sample_machine_readable_code', 
      error_message: 'There is an error in the response from the service.', 
      error: err
   }));
}

And the result in the console is [Error: [object Object]]. I tried accessing its properties both as properties of an array and as an object, but always end up with undefined. JSON.stringify-ing it returns an empty object {}. By "accessing" I mean trying to log the error, f.e. with console.log(err); (which ends up in [object Object]) or err.message or err.Error, or err['Error'], but these were undefined.

I was reading through Node's Error class docs and it seemed like it's okay to pass objects. Am I mistaken? Should I just return a simple custom-constructed object instead of a new Error? Like that:

if (err) {
       return myCallback({
          error_code: 'sample_machine_readable_code', 
          error_message: 'There is an error in the response from the service.', 
          error: err
       });
    }

Cuz I just wanted to use more of what Node offers and to stick to some widely used convention instead of going "my own way".

Answer 1

What you can do, is simply create an instance of Error and assign custom properties to it, like this:

var error = new Error("There is an error in the response from the service"); 
error.error = err; 
error.error_code = "sample_machine_readable_code"

return myCallback(error);