Javascript - Rock, Paper, scissors with switch 语句？ 如果不是什么是替代品？

Question

我正在运行以下代码，它只打印“Draw！” 其他情况下不起作用，我做错了什么？

 const rps = (p1, p2) => { var s = 'scissors'; var p = 'paper'; var r = 'rock'; var ans = ''; switch (rps) { case (p1 == p && p2 == r):case (p1 == s && p2 == p): case (p1 == r && p2 == s): ans = ('Player 1 won!'); break; case (p1 == s && p2 == r): case (p1 == r && p2 == p): case (p1 == p && p2 == s): ans = ('Player 2 won!'); break; default: ans = ('Draw!'); break; } return ans } rps('paper','scissors')

Answer 1

switch将您输入的值（ rps是一个函数）与每种case （这将是true或false ）进行比较。

由于该函数从不匹配布尔值，因此您总是会遇到默认情况。

我究竟做错了什么？

试图将switch用于它并不真正适合的东西。

改用if和else 。

Answer 2

这是另一个范围相同的情况

const compareHands = (computerChoice, playerChoice) => {

        const winner = document.querySelector('.winner');

        switch (computerChoice, playerChoice) {

            case (playerChoice === 'rock' && computerChoice === 'scissors'):
                winner.textContent = "Player 1 Wins";
                return;

            case (playerChoice === 'rock' && computerChoice === 'paper'):
                winner.textContent = "Player 2 Wins";
                return;

            case (playerChoice === 'paper' && computerChoice === 'scissors'):
                winner.textContent = "Player 2 Wins";
                return;

            case (playerChoice === 'paper' && computerChoice === 'rock'):
                winner.textContet = "Player 1 Wins";
                return;

            case (playerChoice === 'scissors' && computerChoice === 'rock'):
                winner.textContent = "Player 2 Wins";
                return;

            case (playerChoice === 'scissors' && computerChoice === 'paper'):
                winner.textContent = "Player 1 Wins";
                return;

            default:
                winner.textContent = "It's Tie";
        }
    }

这里怎么了！！

Answer 3

let rock = 2;
let scissors = 4;
let paper = 8;

let firstPlayerChoice = rock;
let secondPlayerChoice = paper;
 
switch (firstPlayerChoice / secondPlayerChoice) {
  case 1:
    console.log('there is a tie! pick again');
    break;
  case 0.5:
  case 4:
    console.log(`first player won!`);
    break;
  case 2:
  case 0.25:
    console.log(`second player won!`);
    break;
  default:
    console.log('something went wrong!');
}

Answer 4

你好！，

你误解了“开关”的使用，开关的工作原理是这样的：

switch 表达式被评估一次。

将表达式的值与每种情况的值进行比较。

如果匹配，则执行关联的代码块。

来源： https : //www.w3schools.com/js/js_switch.asp

就像昆汀说的，用“if”代替