index.js

var numberOfButtons = document.querySelectorAll("button").length
for (var i=0; i< numberOfButtons; i++){
    document.querySelectorAll("button")[i].addEventListener('click',function handleClick(){
        var buttonHtml = this.innerHTML
        makeSound(buttonHtml)
        buttonAnnimation(buttonHtml)
    })
    
}
document.addEventListener('keydown',function(event){
    makeSound(event.key)
    buttonAnnimation(event.key)
})

function makeSound(key){
    switch (key) {
        case "w":
            var tom1 = new Audio("sounds/tom-1.mp3")
            tom1.play()
            break;
        case "j":
            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 "l":
            var tom4 = new Audio("sounds/tom-4.mp3")
            tom4.play()
            break;
        case "a":
            var crash = new Audio("sounds/crash.mp3")
            crash.play()
            break;
        case "k":
            var kickbass = new Audio("sounds/kick-bass.mp3")
            kickbass.play()
            break;
        case "d":
            var snare = new Audio("sounds/snare.mp3")
            snare.play()
            break;
    
        default:
            break;
    }
}



function buttonAnnimation(currentkey){
    var activeButton = document.querySelector("."+currentkey)
    activeButton.classList.add("pressed")

    setTimeout(function(){
        activeButton.classList.remove("pressed")

    },200)

}