Why does my code add to playerScore every time it calls the playRound function, instead of adding to computerScore?

My project brief suggested calling the playRound function five times in the game function, since I haven't looked into how to "loop" the code to repeat the function calls.

My profile: https://www.theodinproject.com/lessons/foundations-rock-paper-scissors

I tried adding 1 to playerScore or computerScore (they are declared as global variables with value 0) when calling the playRound function.

I tried using the increment operator and I have tried using the addition assignment operator = 1

I thought the winning player's score would be increased by 1.

What actually happened: Each time the playRound function is called, playerScore is incremented by 1, which is inconsistent with the winner.

//write a program to play 'rock, paper, scissors' game against the computer

//COMPUTER CHOICE- generate random choice of weapon
let choice = ['rock', 'paper', 'scissors'];
//select random array element from weapon array
function getComputerChoice() {
  computerChoice = choice[(Math.floor(Math.random() * choice.length))];
  return computerChoice;
}


//USER CHOICE- assign user choice from prompt input
function getPlayerChoice() {
  playerChoice = prompt('Choose your weapon', 'rock, paper or scissors?');
  return playerChoice;
}


//assign values to player variables 
const playerSelection = getPlayerChoice().toLowerCase();
const computerSelection = getComputerChoice();


//message to return to player
let youWin = `You win, ${playerSelection} beats ${computerSelection}`;
let youLose = `You lose, ${computerSelection} beats ${playerSelection}`;
let youDraw = `It's a draw!`;
//put message options into an array
let message = [youWin, youLose, youDraw];


//make global player score variables
let playerScore = 0;
let computerScore = 0;


//function to play one round
function playRound() {

  if (playerSelection == computerSelection) {
    return youDraw;
  } else if (playerSelection == 'rock' && computerSelection == 'paper') {
    computerScore = computerScore++;
    return message[1]; //you lose
  } else if (playerSelection == 'rock' && computerSelection == 'scissors') {
    playerScore++;
    return message[0]; //you win
  } else if (playerSelection == 'paper' && computerSelection == 'rock') {
    playerScore++;
    return message[0]; //you win
  } else if (playerSelection == 'paper' && computerSelection == 'scissors') {
    computerScore++;
    return message[1]; //you lose
  } else if (playerSelection == 'scissors' && computerSelection == 'rock') {
    computerScore++;
    return message[1]; //you lose
  } else if (playerSelection == 'scissors' && computerSelection == 'paper') {
    playerScore++;
    return message[0]; //you win
  } else {
    return ('oops! Type rock, paper or scissors!')
  }
}


//function to play five rounds and report player as winner or loser at the end
function game() {

  //check code: what values are assigned to player selections?
  console.log('player ', playerSelection);
  console.log('computer ', computerSelection);

  playRound();
  playRound();
  playRound();
  playRound();
  playRound();

  return playRound();
}

console.log(game());
console.log(computerScore);
console.log(playerScore);