app.js

let boxes = document.querySelectorAll(".box");
let resetBtn = document.querySelector("#reset-btn");
let newGameBtn = document.querySelector("#new-btn");
let msgContainer = document.querySelector(".msg-container");
let msg = document.querySelector("#msg");

let turnO=true;
let count=0;

const winPatterns = [
    [0,1,2],
    [0,3,6],
    [0,4,8],
    [1,4,7],
    [2,5,8],
    [2,4,6],
    [3,4,5],
    [6,7,8],
];

const resetGame = () => {
    turnO = true;
    count = 0;
    enableBoxes();
    msgContainer.classList.add("hide");
};

boxes.forEach((box) => {
    box.addEventListener("click",() =>{
        if(turnO){
            box.innerText = "O";
            turnO=false;
        }else{
            box.innerText = "X";
            turnO=true;
        }
       box.disabled = true; 
       count++;

       let isWinner = checkWinner();

       if(count === 9 && !isWinner){
        gameDraw();
       }
    });
});

const gameDraw = () => {
    msg.innerText = `Game was a Draw.`;
    msgContainer.classList.remove("hide");
    disableBoxes();
};

const disableBoxes = () => {
    for(let box of boxes) {
        box.disabled = true;
    }
};

const enableBoxes = () => {
    for(let box of boxes) {
        box.disabled = false;
        box.innerText = "";
    }
};

const showWinner = (winner) => {
    msg.innerText = `Congratulations, Winner is ${winner}`;
    msgContainer.classList.remove("hide");
    disableBoxes();
};

const checkWinner = () => {
    for(let pattern of winPatterns ){
        let pos1Val = boxes[pattern[0]].innerText;
        let pos2Val = boxes[pattern[1]].innerText;
        let pos3Val = boxes[pattern[2]].innerText;

        if(pos1Val!= "" && pos2Val != "" && pos3Val != ""){
            if(pos1Val === pos2Val && pos2Val === pos3Val){
                showWinner(pos1Val);
                return true;
            }
        }
    }
};

newGameBtn.addEventListener("click",resetGame);
resetBtn.addEventListener("click",resetGame);