// A basic calculator program
  function calculate(operation, num1, num2) {
      switch (operation) {
          case "add":
              return num1 + num2;
          case "subtract":
              return num1 - num2;
          case "multiply":
              return num1 * num2;
          case "divide":
              return num1 / num2;
          default:
              return "Invalid operation!";
      }
  }
  console.log(calculate("add", 5, 3)); // Output: 8