index.js

document.querySelectorAll("button").forEach(function(button) {
    button.addEventListener('click', function(){
        var buttonInnerHtml= this.innerHTML;
        makeSound(buttonInnerHtml);
        buttonAnimation(buttonInnerHtml);
    })
  });

document.addEventListener("keydown", function(event){
    makeSound(event.key); 
    buttonAnimation(event.key);      
});
  
function makeSound(wantedButton){
    switch(wantedButton){
        case "w":
            var tom1 = new Audio("./sounds/tom-1.mp3");
                 tom1.play();
        break;
        case "a":
            var tom2 = new Audio("./sounds/tom-2.mp3");
                 tom2.play();
        break;
        case "s":
            var tom3 = new Audio("./sounds/tom-3.mp3");
                 tom3.play();
        break;
        case "d":
            var tom4 = new Audio("./sounds/tom-4.mp3");
                 tom4.play();
        break;
        case "j":
            var snare = new Audio("./sounds/snare.mp3");
                 snare.play();
        break;
        case "k":
            var crash = new Audio("./sounds/crash.mp3");
                 crash.play();
        break;
        case "l":
            var kick = new Audio("./sounds/kick-bass.mp3");
                 kick.play();
        break;

        default:
            console.log(wantedButton);
        }
}

function buttonAnimation(currentKey){
    var activebutton = document.querySelector("." + currentKey);
    activebutton.classList.add("pressed");
    setTimeout(function(){
        activebutton.classList.remove("pressed")
    }, 100);
}