project.js

let gameSeq=[];
let userSeq=[];
let btns=["yellow","red","purple","green"];

let started=false;
let level=0;
let h2=document.querySelector("h2");

document.addEventListener("keypress",function (){
    if(started==false){
    console.log("game 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(randColor);
    // console.log(randBtn);
    gameSeq.push(randColor);
    console.log(gameSeq);
    gameFlash(randBtn);
}
function checkAns(idx){
//    console.log("curr level:",level);
    if(userSeq[idx]==gameSeq[idx]){
        if(userSeq.length==gameSeq.length){
            setTimeout(levelUp(),1000);
        };
    }
       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(){
    
   let  btn=this;
   userFlash(btn);
   userColor=btn.getAttribute("id");
   console.log(userColor);
   userSeq.push(userColor);
   checkAns(userSeq.length - 1);
}
let allBtns= document.querySelectorAll(".btn");
for(btn of allBtns){
    btn.addEventListener("click",btnPress);
}
function reset(){
    started=false;
    gameSeq=[];
    userSeq=[];
   level=0;
}