TheOdinProject石头剪刀布项目playRound函数无法循环问题排查

• 前置说明：我是编程初学者，知道同类问题已有较多提问，但仍希望针对我编写的石头剪刀布游戏中playRound函数循环逻辑代码获得针对性反馈。

单独测试功能时可正常返回结果，确认playRound与computerPlay函数可正常工作，能随机返回三种选择结果，测试代码如下：

const playerSelection = "rock";
const computerSelection = computerPlay();
console.log(playRound(playerSelection, computerSelection));

但将playRound函数包裹在game函数中执行时，要么无任何响应，要么弹出两次输入提示后抛出如下错误，错误指向19、50、53行：

Uncaught TypeError: computerPlay is not a function

若按照TheOdinProject教程要求将变量设为playRound函数的入参，console.log会返回undefined，但不会抛出错误。
我查阅过他人的同类问题修复方案，知道当前代码写法不够规范整洁，但不希望直接照搬他人实现，否则无法达到学习效果，希望能修复当前代码使其正常返回5轮游戏的结果。

完整代码如下：

function humanPlayer() {
     let input = prompt("what do you choose, rock, paper, or scissors?");
}
     
// computer makes a move
function computerPlay() {
     computerPlay = Math.floor(Math.random() * 3)
     if (computerPlay === 0 ) {
      return "rock";
     } else if (computerPlay === 1) {
      return "paper";
     } else if (computerPlay === 2) {
      return "scissors";
     }
}
     
function playRound() {
    const playerSelection = humanPlayer(); 
    const computerSelection = computerPlay();   

    // rock
    if(playerSelection === "rock" && computerSelection === "scissors"){
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
    } else if (playerSelection === "rock" && computerSelection === "rock") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
    } else if (playerSelection === "rock" && computerSelection === "paper") {

    return "AHAHAHA. You lost. Loser."
}
// paper
else if (playerSelection === "paper" && computerSelection == "rock") {
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
} else if (playerSelection === "paper" && computerSelection === "paper") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
} else if (playerSelection === "paper" && computerSelection === "scissors") {
      return "AHAHAHA. You lost. Loser."
}
// scissors
else if (playerSelection === "scissors" && computerSelection === "paper") {
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
} else if (playerSelection === "scissors" && computerSelection === "scissors") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
} else if (playerSelection === "scissors" && computerSelection === "rock") {
      return "AHAHAHA. You lost. Loser."
} else {
      return "Good-bye"
}
}
     
function game() {
     for (let i = 0; i < 5; i++) {
         playRound();
     }
}

console.log(game())

当前核心疑问：为什么这段代码无法正常执行循环？

循环逻辑本身没有问题，跑不满5轮是3处代码错误导致的：

1. computerPlay函数自覆盖
   你在computerPlay函数内写了computerPlay = Math.floor(Math.random() * 3)，这行没有声明新变量，直接给同名的函数标识符赋值了数字。第一次调用computerPlay时函数还存在，能正常返回结果，但执行完这行后computerPlay就被覆盖成了0/1/2的数字值，第二次循环再尝试调用computerPlay()时，JS无法对数字做函数调用，直接抛出类型错误，循环直接中断。
2. humanPlayer没有返回值
   你用input接收了prompt的输入内容，但没有写return input把值返回出去，导致playRound里拿到的playerSelection永远是undefined，所有胜负判断分支都不会命中，只会走到最后的else分支返回"Good-bye"。
3. 结果未打印、函数无返回值
   你在game函数里只是调用了playRound()，没有打印或者接收返回值，加上game本身没有return语句，最后console.log(game())必然打印undefined，看不到每轮的对战结果。

function humanPlayer() {
     let input = prompt("what do you choose, rock, paper, or scissors?");
     // 补充返回值，顺手做小写转换避免用户输入大写匹配失败
     return input?.toLowerCase();
}
     
// 电脑出拳逻辑
function computerPlay() {
     // 更换变量名，不要覆盖函数本身
     const randomNum = Math.floor(Math.random() * 3)
     if (randomNum === 0 ) {
      return "rock";
     } else if (randomNum === 1) {
      return "paper";
     } else if (randomNum === 2) {
      return "scissors";
     }
}
     
function playRound() {
    const playerSelection = humanPlayer(); 
    const computerSelection = computerPlay();   

    // 原有胜负判断逻辑不需要改动
    if(playerSelection === "rock" && computerSelection === "scissors"){
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
    } else if (playerSelection === "rock" && computerSelection === "rock") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
    } else if (playerSelection === "rock" && computerSelection === "paper") {
      return "AHAHAHA. You lost. Loser."
    } else if (playerSelection === "paper" && computerSelection == "rock") {
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
    } else if (playerSelection === "paper" && computerSelection === "paper") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
    } else if (playerSelection === "paper" && computerSelection === "scissors") {
      return "AHAHAHA. You lost. Loser."
    } else if (playerSelection === "scissors" && computerSelection === "paper") {
      return "Good job! You had a one in three chance to win and you did. Congratulations...";
    } else if (playerSelection === "scissors" && computerSelection === "scissors") {
      return "Oh, Well. It could be worse. You Could of Chosen paper."
    } else if (playerSelection === "scissors" && computerSelection === "rock") {
      return "AHAHAHA. You lost. Loser."
    } else {
      return "Good-bye"
    }
}
     
function game() {
     for (let i = 0; i < 5; i++) {
         // 打印每轮结果，否则看不到返回内容
         console.log(`第${i+1}轮结果：${playRound()}`);
     }
}

// 直接调用即可，不需要额外console.log
game()

改完以上三点就能正常执行完5轮循环，看到每轮的对战结果。

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