javascript - Rock, Paper, Scissors Game - userChoice 未定义，但已定义...我认为？

Question

当我执行 playGame();我想展示这个:您已选择 ${userChoice)，计算机已选择 ${computerChoice}。获胜者是 ${determineWinner}。根据我的理解，userchoice 定义在我的代码顶部，computerChoice 定义在 computerChoice 部分。所以我不明白。感谢您的帮助。

相反，我只是收到一条错误消息:ReferenceError: userChoice is not defined 在玩游戏。

已修复:这就是我所做的，但不确定它是如何或为什么起作用的:

function playGame(){
  userChoice = "rock";
  computerChoice = getComputerChoice();
  console.log(`The user chose ${userChoice}. The computer chose ${computerChoice}. ${determineWinner(userChoice,computerChoice)}`)
}
playGame();

---

//We're taking the userInput and converting it to lowercase letters and storing it within userChoice
    function getUserChoice(userInput){
      let userChoice = userInput.toLowerCase();
        if(userChoice === "rock" || userChoice === "paper" || userChoice === "scissors"){return userChoice;}
        else{return "That hand doesn't exist.";}
    }

    //We're making a number and converting it to an eqvivalent string
    function getComputerChoice(){
      let computerChoice = Math.floor(Math.random()*3);
        if(computerChoice === 0){return "rock";}
        else if(computerChoice === 1){return "scissors";}
        else if(computerChoice === 2){return "paper";}
            else{return "Input not valid.";}
    }

    //Determining the winner based upon the input and the computer's choice
    function determineWinner(userChoice, computerChoice){
        //Having a tie
        if (userChoice === computerChoice){return "It's a tie!";}
        //If the user types in scissors
      else if(userChoice === "scissors"){
        if(computerChoice === "rock"){return "Computer wins! Rock kills scissors.";}
        else if(computerChoice ==="paper"){return "User wins! Scissors kill paper.";}
      }
        //If the user types in paper
      else if(userChoice === "paper"){
        if(computerChoice === "rock"){return "User wins! Paper kills rock.";}
        else if(computerChoice === "scissors"){return "Computer wins! Scissors kill paper.";}
      }
        //If the user types in rock
      else if(userChoice === "rock"){
        if(computerChoice === "paper"){return "Computer wins! Paper kills rock.";}
        else if(computerChoice === "scissors"){return "User wins! Rock kills scissors."};
      }
    }

    //Function that embodies the other functions and executes the game.
    function playGame(){
      console.log(`You chose ${userChoice}`);
    }
    playGame();

Answer 1

您的变量 userChoice 未在函数 playGame 的上下文中定义，这就是您看到引用错误的原因:

function playGame() {
  console.log(`You chose ${userChoice}`); // this is not defined
}

playGame();