index.js

var numberOfDrumButton = document.querySelectorAll(".drum").length;

// Interaction with mouse click
for (i = 0; i < numberOfDrumButton; i++ ) {
    document.querySelectorAll(".drum")[i].addEventListener("click", function handleClick() {    
    var buttonInnerHTML = this.innerHTML.toLowerCase();
    makeSound(buttonInnerHTML);
    buttonPress(buttonInnerHTML);
});
};


// Interaction with keyboard
document.addEventListener('keydown', function(event) {
    makeSound(event.key);
    buttonPress(event.key);
});



function makeSound(key) {
    switch (key) {
        case 'w':
            var crash = new Audio('sounds/crash.mp3');
            crash.play();
            break;
        case 'a':
            var kick = new Audio('sounds/kick-bass.mp3');
            kick.play();
            break;
        case 's':
            var snare = new Audio('sounds/snare.mp3');
            snare.play();
            break;
        case 'd':
            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 'k':
            var tom3 = new Audio('sounds/tom-3.mp3');
            tom3.play();
            break;
        case 'l':
            var tom4 = new Audio('sounds/tom-4.mp3');
            tom4.play();
            break;
        default:
            console.log(buttonInnerHTML);
            break;
    }
};


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