index.js

// for (var i=0;i<=document.querySelectorAll(".drum").length;i++){
//     document.querySelectorAll("button")[i].addEventListener("click", function() {
//     alert("I Got Clicked!");
//     });
// }


//Detecting Button Press
var numberOfDrumButtons = document.querySelectorAll(".drum").length;

for (var i=0; i<numberOfDrumButtons; i++){

    document.querySelectorAll(".drum")[i].addEventListener("click", function () {

        var buttonInnerHTML = this.innerHTML

        makeSound(buttonInnerHTML);

        buttonAnimation(buttonInnerHTML);

    });

}

//Detecting Keyboard Press
document.addEventListener("keydown",function(event){

    makeSound(event.key);

    buttonAnimation(event.key);
});

function makeSound(key){

    switch (key) {
        case "w":
            var tom1 = new Audio("sounds/tom-1.mp3");
            tom1.play();
            break;

        case "a":
            var crash = new Audio("sounds/crash.mp3");
            crash.play();
            break;

        case "s":
            var tom2 = new Audio("sounds/tom-2.mp3");
            tom2.play();
            break;

        case "d":
            var kick = new Audio("sounds/kick-bass.mp3");
            kick.play();
            break;
        
        case "j":
            var tom3 = new Audio("sounds/tom-3.mp3");
            tom3.play();
            break;

        case "k":
            var snare = new Audio("sounds/snare.mp3");
            snare.play();
            break;

        case "l":
            var tom4 = new Audio("sounds/tom-4.mp3");
            tom4.play();
            break;

        default:
            console.log(buttonInnerHTML);
    }
}        

function buttonAnimation(currentKey){
    
    var activeButton = document.querySelector("." + currentKey);
    activeButton.classList.add("pressed");

    setTimeout(function() {
        activeButton.classList.remove("pressed")
    }, 100);

}

        // this.style.color="white";   
        //soundname = "tom-"+i+".mp3";
        // var audio = new Audio("sounds/tom-1.mp3");
        // audio.play();