text: function play(e) {
      const key = get(".key", e.keyCode);
      const audio = get("audio", e.keyCode);
  
      if (audio) {
          audio.currentTime = 0;
          audio.play();
          key.classList.add("playing");
          key.addEventListener("transitionend", removeTransition);
      }
  }
  
  function removeTransition(e) {
      if (e.propertyName === "transform") {
          this.classList.remove("playing");
      }
  };
  
  function get(el, code) {
      return document.querySelector(`${el}[data-key="${code}"]`);
  }
  
  window.addEventListener("keydown", play);