How do I make a value change in one function and then try it in another function?

Question

This is my code

let w = 0;
let l = 0;
function playRound (playerSelection, computorSelection) {
    if (playerSelection == computorSelection) {
        console.log("You tied, try again.");
    } else if ((playerSelection - computorSelection + 3) % 3 == 1) {
        console.log("You win!");
        w++;
    } else {
        console.log("You lose!");
        l++;
    }
}

function game() {
    playerSelection();
    playRound();
    if (w == 5) {
        console.log("You've won 5 times! Well done!");
    } else if (l == 5) {
        console.log("You've lost 5 times. Too bad.");
    } else {
        playerSelection();
        playRound();
    }
}

There is more code above this but that code all works fine. I want the playRound function to change the value of l and w depending on if the round is a win or a loss and the game function to continue the game until either 5 losses or 5 wins have happened.

When I call the game function the code starts correct, but it always gives a tie as the first round, starts it again and returns undefined. What am I doing wrong?

Answer 1

In your game function, you're calling playRound() without passing any arguments to it.

However, playRound accepts two, playerSelection and computorSelection, and in its first line compares the two:

if (playerSelection == computorSelection) {

Since both values are undefined (due to their not being passed in), that condition evaluates to true and the function declares a tie and does not increment w or l.