code: func consoleOutput(call otto.FunctionCall) otto.Value {
  	output := []string{"JS:> "}
  	for _, argument := range call.ArgumentList {
  		output = append(output, fmt.Sprintf("%v", argument))
  	}
  	fmt.Fprintln(os.Stderr, strings.Join(output, " "))
  	return otto.Value{}
  }
docs: // consoleOutput is an override for the console.log and console.error methods to
  // stream the output into the configured output stream instead of stdout.