HOME.JS

var numberOfDrumButtons = document.querySelectorAll(".drum").length;
for(var i=0; i<numberOfDrumButtons; i++)
{
    document.querySelectorAll(".drum")[i].addEventListener("click" , function()
    {
        var buttonInnerHTML = this.innerHTML;
        sound(buttonInnerHTML);
        buttonAnimation(buttonInnerHTML);
    });
}

document.addEventListener("keypress" , function(event)
{
    sound(event.key);
    buttonAnimation(event.key);
});

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

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

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

        case "f":
            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;
    }
}

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

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