Javascript: Custom error with stack

error.js

/*
http://jsbin.com/rolojuhuya/1/
https://stackoverflow.com/questions/8802845/inheriting-from-the-error-object-where-is-the-message-property
https://stackoverflow.com/questions/783818/how-do-i-create-a-custom-error-in-javascript
*/

function CustomError(message, somethingElse) {
  var error = Error.call(this, message);

  this.name = 'CustomError';
  this.message = error.message;
  this.stack = error.stack;
  this.customProperty = somethingElse;
}

CustomError.prototype = Object.create(Error.prototype);
CustomError.prototype.constructor = CustomError;


var customError = new CustomError('some error message', 42);

console.log(customError.name + ' => CustomError');
console.log(customError.message + ' => some error message');
console.log(customError.customProperty + ' => 42');
console.log((customError instanceof Error) + ' => true');
console.log((customError instanceof CustomError) + ' => true');

console.log('constructor: ' + customError.constructor);
console.log('toString: ' + customError.toString());
console.log('stack: ' + customError.stack);