我的函数在第一个语句后不返回运行

Question

因此，我正在制作一个Rock Paper Scissors函数，该函数需要取值并返回：输赢或并列，但在第一个程序段之后不返回任何东西。这是我的代码：

function playRound(playerSelection, computerSelection){

   if(playerSelection === "rock" && computerSelection === "scissors") {
     return "wins";
    }
     else if(computerSelection === "paper") {
       return "lost"  
     }
       else{
       return "tied";
       }



if(playerSelection === "paper" && computerSelection === "rock") {
     return "wins";
    }
     else if(computerSelection === "scissors") {
       return "lost"  
     }
       else{
       return "tied";
       }



   if(playerSelection === "scissors" && computerSelection === "paper") {
     return "wins";
    }
     else if(computerSelection === "rock") {
       return "lost";
     }
       else{
       return "tied";
       }

   }

Answer 1

因为您的逻辑有缺陷，它没有返回任何内容。

您的逻辑是（从第一个块开始）：

• 情况1：playerSelection === "rock" && computerSelection === "scissors"
• 情况2：computerSelection === "paper"
• 情况3：“其他一切”

我认为您的代码所指的是实际上将playerSelection === "rock"应用于整个的第一块。因此，您将需要一些嵌套的if语句来捕获它。

您修改后的逻辑应类似于：

如果（playerSelection === "rock"）：

• 情况1：computerSelection === "scissors"
• 情况2：computerSelection === "paper"
• 情况3：“其他一切”

话虽这么说，您对“其他所有内容”的检查有点重复，并且可以做一些进一步的优化。话虽如此，我已经为您优化了代码。

function playRound(playerSelection, computerSelection) {
    if (playerSelection === computerSelection) {
        // may be worth validating that rock/paper/scissors were the only possible inputs here
        return "tied";
    }

    switch (playerSelection) {
        case "rock":
            if (computerSelection === "scissors") return "wins";
            if (computerSelection === "paper") return "lost";
            break;

        case "paper":
            if (computerSelection === "rock") return "wins";
            if (computerSelection === "scissors") return "lost";
            break;

        case "scissors":
            if (computerSelection === "paper") return "wins";
            if (computerSelection === "rock") return "lost";
            break;
    }

    // error handling (no match)
    return null;
}