index.js

var noofdrums = document.querySelectorAll(".drum").length;
for (let i = 0; i < noofdrums; i++) {
    document.querySelectorAll(".drum")[i].addEventListener("click",function(){
        var buttoninnerhtml = this.innerHTML;
        makesound(buttoninnerhtml);
        buttonAnimation(buttoninnerhtml);
    });
}
document.addEventListener("keypress", function(event){
    makesound(event.key); 
    buttonAnimation(event.key);
})
function makesound(key){
    switch (key) {
        case "w":
            var audio = new Audio("sounds/tom-1.mp3");
            audio.play(); 
            break;
        case "a":
            var audio = new Audio("sounds/tom-2.mp3");
            audio.play(); 
            break;
        case "s":
            var audio = new Audio("sounds/tom-3.mp3");
            audio.play(); 
            break;
        case "d":
            var audio = new Audio("sounds/tom-4.mp3");
            audio.play(); 
            break;
        case "j":
            var audio = new Audio("sounds/snare.mp3");
            audio.play(); 
            break;
        case "k":
            var audio = new Audio("sounds/crash.mp3");
            audio.play(); 
            break;
        case "l":
            var audio = new Audio("sounds/kick-bass.mp3");
            audio.play(); 
        default:
            console.log(key);
    }   
}

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

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