game.js

var buttonColours = ["red", "blue", "green", "yellow"];
var gamePattern = [];
var userClickedPattern = [];

var started =false;
var level =0;

$(document).keypress(function(){
    if(!started){
        $("#level-title").text("Level "+level);
        nextSequence()
        started =true;
    }
});

$(".btn").click(function() {

  var userChosenColour = $(this).attr("id");
    
  userClickedPattern.push(userChosenColour);
  playSound(userChosenColour);
  animatePress(userChosenColour);
  checkAnswer(userClickedPattern.length-1);
});
function checkAnswer(currentLevel) {

    if (gamePattern[currentLevel] === userClickedPattern[currentLevel]) {

      console.log("success");

      if (userClickedPattern.length === gamePattern.length){

        setTimeout(function () {
          nextSequence();
        }, 1000);

      }

    } else {

      console.log("wrong");
        playSound("wrong");

      $("body").addClass("game-over");
      setTimeout(function () {
        $("body").removeClass("game-over");
      }, 200);

      $("#level-title").text("Game Over, Press Any Key to Restart");
        startOver();
    }

}
function nextSequence() {
    userClickedPattern = [];
    level++;
     $("#level-title").text("Level " + level);
  var randomNumber = Math.floor(Math.random() * 4);

  var randomChosenColour = buttonColours[randomNumber];

  gamePattern.push(randomChosenColour);

    $("#"+randomChosenColour).fadeIn(100).fadeOut(100).fadeIn(100);
    playSound(randomChosenColour);
}

function playSound(name) {
  var audio = new Audio("sounds/" + name + ".mp3");
  audio.play();
}

function animatePress(currentColor) {

  $("#" + currentColor).addClass("pressed");
  setTimeout(function () {
    $("#" + currentColor).removeClass("pressed");
  }, 100);
}

function startOver() {

  level = 0;
  gamePattern = [];
  started = false;
}