index.js

const buttons = document.querySelectorAll("button");
for (let i = 0; i < buttons.length; i++) {
    buttons[i].addEventListener("click", function () {
        makeSound(buttons[i].textContent);
        buttonAnimation(buttons[i].textContent);
    }
)
}

document.addEventListener("keypress", function (e) {
    makeSound(e.key);
    buttonAnimation(e.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-1.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();
        break;
      default:
        console.log(buttons[i].textContent);
    }
}

function buttonAnimation(key) {
    var activeButton = document.querySelector("." + key);

    activeButton.classList.add("pressed");
    setTimeout(
        function () {
            activeButton.classList.remove("pressed");
        }, 0.1
    )
}