篮球得分计算函数返回else提示与undefined问题求助

我原本认为这段代码逻辑正确，功能是根据罚球（free throws）、两分球（2 pointers）、三分球（3 pointers）的数量计算篮球总得分。但调用totalBasketballScore(1, 2, 4)并通过console.log输出时，结果为'All Entries Must Be a Number'和undefined，请问需要修改哪里才能得到正确的得分？

原代码：

function totalBasketballScore(numberFreeThrows, numberMidRange, numberThreePointers) {
  const freeThrows = 1;
  const midRange = 2;
  const threePointers = 3;

  if (typeof numberFreeThrows === 'number' && numberMidRange === 'number' && numberThreePointers === 'number') {
    let totalFreeThrows = freeThrows * numberFreeThrows;
    let totalMidRange = midRange * numberMidRange;
    let totalThreePointers = threePointers * numberThreePointers;
    let gameTotal = totalFreeThrows + totalMidRange + totalThreePointers;
    return gameTotal;

  } else {
    console.log('All Entries Must Be a Number');
  }
}
console.log(totalBasketballScore(1, 2, 4));

问题原因 #

类型判断逻辑错误：条件中仅对numberFreeThrows使用了typeof判断类型，而numberMidRange和numberThreePointers直接与字符串'number'做全等比较。由于传入的参数是数值类型，和字符串'number'全等判断结果为false，导致条件永远不成立，每次都会进入else分支：打印错误提示，且因为else分支没有返回值，函数默认返回undefined，最终console.log输出这两个结果。

修复方案 #

修正类型判断条件，为每个参数都添加typeof检查，同时可给else分支补充返回值避免undefined：

function totalBasketballScore(numberFreeThrows, numberMidRange, numberThreePointers) {
  const freeThrows = 1;
  const midRange = 2;
  const threePointers = 3;

  // 为所有参数添加typeof类型判断
  if (typeof numberFreeThrows === 'number' && typeof numberMidRange === 'number' && typeof numberThreePointers === 'number') {
    const totalFreeThrows = freeThrows * numberFreeThrows;
    const totalMidRange = midRange * numberMidRange;
    const totalThreePointers = threePointers * numberThreePointers;
    const gameTotal = totalFreeThrows + totalMidRange + totalThreePointers;
    return gameTotal;
  } else {
    console.log('All Entries Must Be a Number');
    // 可选：返回一个默认值，避免函数返回undefined
    return 0;
  }
}
console.log(totalBasketballScore(1, 2, 4)); // 输出17

修复后调用totalBasketballScore(1, 2, 4)会得到正确结果17（计算逻辑：11 + 22 + 4*3 = 1+4+12=17）。

内容的提问来源于stack exchange，提问作者HarrisWeinblatt