Crea una calculadora con "if" que opere con dos números. La calculadora

function calculator(firstNumber, secondNumber, action) {
  if (action == 'sum') {
    return firstNumber + secondNumber;
  } else if (action == 'rest') {
    return firstNumber - secondNumber;
  } else if (action == 'multiply') {
    return firstNumber * secondNumber;
  } else if (action == 'divide') {
    return firstNumber / secondNumber;
  } else {
    return 'Error';
  }
}