javascript - JavaScript 中的可选参数

Question

为什么如果缺少剩余参数，该函数不会抛出错误？

showStatistics("Mark Teixeira", "New York Yankees", "1st Base");

这是一个定义的函数:

function showStatistics(name, team, position, average, homeruns, rbi) {
  document.write("<p><strong>Name:</strong> " + arguments[0] + "<br />");
  document.write("<strong>Team:</strong> " + arguments[1] + "<br />");

  if (typeof arguments[2] === "string") {
    document.write("<strong>Position:</strong> " + position + "<br />"); 
  }
  if (typeof arguments[3] === "number") {
    document.write("<strong>Batting Average:</strong> " + average + "<br />");
  }
  if (typeof arguments[4] === "number") {
    document.write("<strong>Home Runs:</strong> " + homeruns + "<br />");
  }
  if (typeof arguments[5] === "number") {
    document.write("<strong>Runs Batted In:</strong> " + rbi + "</p>"); 
  }
}

Answer 1

任何未传递的参数在函数内都显示为未定义。 JavaScript 中没有方法重载。