Question 264731 in Javascript Question posted in
A very good W3school tutorial can be found here.

rock paper scissors javascript code doesnt work. I made this as my first project and i dont know at all why it doesnt work

function playRound(playerSelection, computerSelection) {
   
    if (playerSelection == computerSelection) {
        console.log("its a tie")

       } else if (playerSelection == "rock" && computerSelection == "paper") {
        return "you lose" 

     } else if (playerSelection == "rock" && computerSelection == "scissors") {
        
        return "you win"  

     }  else if (playerSelection == "paper" && computerSelection == "scissors") {
        return "you lose" 

     } else if (playerSelection == "paper" && computerSelection == "rock") {
        return "you win" 

     } else if (playerSelection == "scissors" && computerSelection == "rock") {
        return "you lose" 

     } else if (playerSelection == "scissors" && computerSelection == "paper") {
        return "you win" 
     }    
}
   
let playerSelection = parseInt(prompt("input rock paper or scissors"))
let computerSelection = Math.random();

if (computerSelection < 0.34){
  computerSelection = "rock"
} else if(computerSelection <=0.67){
  computerSelection = "paper"
} else {
  computerSelection = "scissors"
}

console.log(playRound(playerSelection, computerSelection))

I know its probably not the best method but i thought it should get the job done, any help is useful as i don’t know where the mistake can be, thank you. I looked at some other posts but couldn’t find the solution. This is my first post so if there is some info missing or something just let me know!

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2

Answers


  1. 0

    There are a few issues,

    1. not returning when it’s tied.
    2. converting the prompt into an int.

    Try the following

    function playRound(playerSelection, computerSelection) {
  if (playerSelection === computerSelection) {
    return 'its a tie';
  } else if (playerSelection === 'rock' && computerSelection === 'paper') {
    return 'you lose';
  } else if (playerSelection === 'rock' && computerSelection === 'scissors') {
    return 'you win';
  } else if (playerSelection === 'paper' && computerSelection === 'scissors') {
    return 'you lose';
  } else if (playerSelection === 'paper' && computerSelection === 'rock') {
    return 'you win';
  } else if (playerSelection === 'scissors' && computerSelection === 'rock') {
    return 'you lose';
  } else if (playerSelection === 'scissors' && computerSelection === 'paper') {
    return 'you win';
  }
}

let playerSelection = prompt(`Type 'rock' or 'paper' or 'scissors'`)

let computerSelection = Math.random();
if (computerSelection < 0.34) {
  computerSelection = 'rock';
} else if (computerSelection <= 0.67) { 
  computerSelection = 'paper';
} else {
  computerSelection = 'scissors';
}

console.log(playRound(playerSelection, computerSelection));
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  2. 0

    You shouldn’t be using parseInt because the user will be entering string data, not numbers.

    You also need to move some of your console.log() statements around a bit, but other than that, you’re good to go!

    // No parseInt when the input is strings that need to be strings
let playerSelection = prompt("input rock paper or scissors");
let computerSelection = Math.random();

if (computerSelection < 0.34) {
  computerSelection = "rock"
} else if(computerSelection <=0.67) {
  computerSelection = "paper"
} else {
  computerSelection = "scissors"
}

playRound(playerSelection, computerSelection)

function playRound(playerSelection, computerSelection) {
    // Instead of returning in each branch, just set the value of a string that you can
    // report at the end of the function.
    let result = "";
   
    if (playerSelection == computerSelection) {
       result = "its a tie"
     } else if (playerSelection == "rock" && computerSelection == "paper") {
        result = "you lose" 
     } else if (playerSelection == "rock" && computerSelection == "scissors") {
        result =  "you win"  
     }  else if (playerSelection == "paper" && computerSelection == "scissors") {
        result =  "you lose" 
     } else if (playerSelection == "paper" && computerSelection == "rock") {
        result =  "you win" 
     } else if (playerSelection == "scissors" && computerSelection == "rock") {
        result =  "you lose" 
     } else if (playerSelection == "scissors" && computerSelection == "paper") {
        reresult = "you win" 
     }
     
     console.log("Compupter picked: " + computerSelection, "You picked " + playerSelection, result);
}
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