index.js

// Detecting button press

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

for (var i = 0; i < numberOfDrumButtons; i++) {

  document.querySelectorAll(".drum")[i].addEventListener("click", function() {

    var buttonInnerHTML = this.innerHTML;

    makeSound(buttonInnerHTML);

  });
}

    //Detecting key press

document.addEventListener("keydown",function(event){

  makeSound(event.key);

});

function makeSound(key){

  switch (key) {

    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 kickBass = new Audio('sounds/kick-bass.mp3');
      kickBass.play();
      break;


    default:

  }
}