code: function () {
  		var message = this.message;
  		var name = this.name;
  		var url = this.url;
  		var result = name;
  		if (message) {
  			result +=  ': ' + message;
  		}
  		if (url) {
  			result += ' (' + url + ')';
  		}
  		return result;
  	}
docs: Display the contents of this error. Always shows the name. If the message
  exists it is also displayed. A URL to, for example, help documentation
  can be displayed as well.
  @return {String} Contents of this error