如何使我的函数 return 成为未定义以外的值？

Question

我正在尝试完成奥丁计划中的石头剪刀布挑战。我卡住了；我不知道为什么当我运行我的代码时，我的函数 playRound returns 未定义。任何帮助将不胜感激。

  const computerPlay = () => { //Randomly returns 'Rock', 'Paper', or 'Scissors'
  let choices = ['rock', 'paper', 'scissors'];
  let computerChoice = choices[Math.floor(Math.random() * choices.length)];
  return computerChoice;
}

const playRound = (playerSelection, computerSelection) => {
  playerSelection = playerSelection.toLowerCase;
  if (playerSelection === computerSelection) {
    return "It's a tie";
  } else {
    switch (playerSelection.toLowerCase) {
      case 'rock':
        switch (computerSelection) {
          case 'paper':
            return "You Lose! Paper beats Rock";
          case 'scissors':
            return "You Win! Rock beats Scissors";
        }
      case 'paper':
        switch (computerSelection) {
          case 'rock':
            return "You Win! Paper beats Rock";
          case 'scissors':
            return "You Lose. Scissors beats Paper"
        }
      case 'scissors':
        switch(computerSelection) {
          case 'rock':
            return "You Lose. Rock beats scissors";
          case 'paper':
            return "You Win. Scissors beats Paper"
        }
      }

  }
}

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

Answer 1

您在 toLowerCase 方法中缺少括号。

 const computerPlay = () => { //Randomly returns 'Rock', 'Paper', or 'Scissors'
  let choices = ['rock', 'paper', 'scissors'];
  let computerChoice = choices[Math.floor(Math.random() * choices.length)];
  return computerChoice;
}

const playRound = (playerSelection, computerSelection) => {
  playerSelection = playerSelection.toLowerCase();
  if (playerSelection === computerSelection) {
    return "It's a tie";
  } else {
    switch (playerSelection.toLowerCase()) {
      case 'rock':
        switch (computerSelection) {
          case 'paper':
            return "You Lose! Paper beats Rock";
          case 'scissors':
            return "You Win! Rock beats Scissors";
        }
      case 'paper':
        switch (computerSelection) {
          case 'rock':
            return "You Win! Paper beats Rock";
          case 'scissors':
            return "You Lose. Scissors beats Paper"
        }
      case 'scissors':
        switch(computerSelection) {
          case 'rock':
            return "You Lose. Rock beats scissors";
          case 'paper':
            return "You Win. Scissors beats Paper"
        }
      }

  }
}

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

Answer 2

您缺少括号 -> .toLowerCase()

Answer 3

const sentence = 'My Dog Is Brown';

console.log(sentence.toLowerCase());
// expected output: "my dog is brown"

.toLowerCase()方法returns将字符串的值转换为小写
.toLowerCase() 不影响字符串本身的值。

如何使我的函数 return 成为未定义以外的值？

How can I make my function return a value other than undefined?

javascript

function

switch-statement

undefined