app.js

let gameSeq=[];
let userSeq=[];

let started=false;
let level=0;
let btns=["yellow","red","purple","green"];

h2=document.querySelector('h2');

document.addEventListener("keypress",function(){
    if (started == false){
        console.log("game is started")
        started = true;

        levelUp();
    }
})

function gameFlash(btn){
    btn.classList.add("flash");
    setTimeout(function(){
        btn.classList.remove("flash")
    },250);
}

function userFlash(btn){
    btn.classList.add("userflash");
    setTimeout(function(){
        btn.classList.remove("userflash")
    },250);
}

function levelUp(){
    userSeq=[];
    level++;
    h2.innerText= `Level ${level}`;

    let randIdx=Math.floor(Math.random()*3);
    let randColor=btns[randIdx];
    let randBtn=document.querySelector(`.${randColor}`)

    // console.log(randIdx);
    // console.log(randBtn);
    // console.log(randColor);
    gameSeq.push(randColor);
    console.log(gameSeq);

    gameFlash(randBtn);
}

function checkAns(idx){
    // console.log("current level:",level);
    // let idx= level - 1;
    if (userSeq[idx] === gameSeq[idx]){
        if(userSeq.length== gameSeq.length){
            setTimeout(levelUp,1000);  
        }
        // console.log("same value")
    }
    else{
        h2.innerHTML = `Game over!! Your score was <b> ${level} </b> <br> Press any key to start.`
        document.querySelector("body").style.backgroundColor = "red";
        setTimeout(function(){
            document.querySelector("body").style.backgroundColor = "white";
        },150)
        reset();
    }

}

function btnPress(){
    console.log(this)
    let btn=this;
    
    userFlash(btn)
    // console.log("btn was pressed")

    userColor=btn.getAttribute("id");
    console.log(userColor);
    userSeq.push(userColor);

    checkAns(userSeq.length - 1);
    // level++;
}

let allBtns=document.querySelectorAll(".btn");
for (btn of allBtns){
    btn.addEventListener("click",btnPress);
}

function reset(){
    started = false;
    gameSeq=[];
    userSeq =[];
    level=0;
}