每次使用同一个 JavaScript 函数时，如何获得一个新值？

Question

这个问题与The Odin Project Rock Paper Scissors JavaScript Fundamentals course直接相关。

我已经成功地制作了一个为计算机随机挑选“石头”、“纸”或“剪刀”的功能，称为“computerPlay”。

    function computerPlay() {
    const gameArray = ['Rock', 'Paper', 'Scissors'];
    const random = Math.floor(Math.random() * gameArray.length);
    return gameArray[random];
 }

我制作了另一个函数来接受玩家输入的“rock”、“paper”、“scissors”（或分别为 1、2、3），在另一个名为“playerPlay”的函数中不考虑大小写。

function playerPlay() {
   console.log ("Do you choose 'Rock' (1), 'Paper' (2), or 'Scissors' (3)?");
   let playerChoice = prompt("Do you choose 'Rock' (1), 'Paper' (2), or 'Scissors' (3)?");
   if (playerChoice.toLowerCase() === "rock" || parseInt(playerChoice) === 1) {
      playerChoice = "Rock";
   } else if (playerChoice.toLowerCase() === "paper" || parseInt(playerChoice) === 2) {
      playerChoice = "Paper";
   }
   else if (playerChoice.toLowerCase() === "scissors" || parseInt(playerChoice) === 3) {
      playerChoice = "Scissors";
   }
   else if (playerChoice.toLowerCase() !== "rock" || "scissors" || "paper" || parseInt(playerChoice) !== 1 || 2 || 3) {
      alert("Please try to enter your value again :)")
      playerSelection();
   }
   else {
      console.log("Not sure what's going on, hold on to yer butts ;)")
   }
   return playerChoice;
}

函数playerPlay()保存到const变量playerSelection，函数computerPlay()保存到const变量computerSelection。

 // Create a variable to store player's choice
 const playerSelection = playerPlay();

 // Create a variable to store computer's choice
 const computerSelection = computerPlay();

然后在 playRound() 函数中使用这两个 const 变量，该函数运行一组比较以查看然后 console.log 并返回玩家或计算机是否赢得了石头、纸和剪刀的回合。

/* Write a function that plays a single round of Rock Paper Scissors. The function should take two parameters - the playerSelection and 
computerSelection - and then return a string that declares the winner of the round like so: "You Lose! Paper beats Rock" */

function playRound(playerSelection, computerSelection) {
   if (computerSelection.toLowerCase() === playerSelection.toLowerCase()) {
      console.log("It's a draw!");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "rock" && playerSelection.toLowerCase() === "scissors") {
      console.log("Rock beats scissors! You lose :(");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "scissors" && playerSelection.toLowerCase() === "rock") {
      console.log("Rock beats scissors! You win :D");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "scissors" && playerSelection.toLowerCase() === "paper") {
      console.log("Scissors beats paper! You lose :(");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "paper" && playerSelection.toLowerCase() === "scissors") {
      console.log("Scissors beats paper! You win :D");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "paper" && playerSelection.toLowerCase() === "rock") {
      console.log("Paper beats rock! You lose :(");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else if (computerSelection.toLowerCase() === "rock" && playerSelection.toLowerCase() === "paper") {
      console.log("Paper beats rock! You win :D");
      return("Your Choice: " + playerSelection + ". " + "Computer: " + computerSelection);
   } else {
      console.log("I'm not sure what, but something went worng :(");
   }
}

我的问题来自于我需要重复 playRound() 函数 5 次，并且每一轮都不同。

/* Write a NEW function called game(). Use the previous function inside of this one to play a 5 round game that keeps score and reports 
a winner or loser at the end. */
// Define function / rule for winning and keeping track of score and determining winner for 5 rounds of game
// Make each round reset the computer choice and get new input from the player.

function game() {
   roundOne;
   roundTwo;
   roundThree;
   roundFour;
   roundFive;
}

const roundOne = playRound(playerSelection, computerSelection);
const roundTwo = playRound(playerSelection, computerSelection);
const roundThree = playRound(playerSelection, computerSelection);
const roundFour = playRound(playerSelection, computerSelection);
const roundFive = playRound(playerSelection, computerSelection);

// Print results of game round
console.log(game(playerSelection, computerSelection));

我最近尝试创建 5 个新的 const 变量（roundOne、roundTwo...roundFive）来包含“playRound(playRound(playerSelection,computerSelection);”功能。我还尝试将 playerSelection 和 computerSelection const 变量更改为 let，认为 const 的性质可能会将值锁定到位，直到我重新加载页面。我认为这可能是一个范围问题，但我不明白它到底在哪里——这就是我想在这里问的原因。主要问题是玩家输入的值和计算机随机生成的值在 5 次重复回合中始终相同。如何为每个重复的回合打印不同的值？这可能与我如何使用“gameArray”（在 computerPlay() 函数中）和“playerChoice”（在 playerPlay() 函数中）有关吗？

如果这比需要的时间长得多，我深表歉意。我也会继续调查。非常感谢您。

（这是我第一个实际的 JavaScript 创建/任何类型的项目，所以任何一般的反馈，或者我如何发布/提出这个问题，也将不胜感激。谢谢！）

Answer 1

据我所知，您只设置了一次常量playerSelection 和computerSelection（它们是常量，因此无法修改）。然后，您将这些传递给您的 playRound 函数，该函数处理相同的 const 5 次。考虑完全删除这些 const 并像这样编写游戏函数：

function game() {
   //Play game 5 times
   for (let i = 0; i < 5; i++) {
     const playerSelection = playerPlay();
     const computerSelection = computerPlay();
     // Call playRound function, passing in newly returned values
     // from the playerPlay and computerPlay functions
     const currentRound = playRound(playerSelection, computerSelection);
     // Log our result
     console.log(currentRound);
   }
}

或者，更简洁：

function game() {
   //Play game 5 times
   for (let i = 0; i < 5; i++) {
     // Call playRound function, passing in newly returned values
     // from the playerPlay and computerPlay functions and log to console
     console.log(playRound(playerPlay(), computerPlay()));
   }
}