Событие Зажатой ЛКМ

const piano = document.querySelector(".piano");
const collectionPiano = document.querySelectorAll(".piano-key");
 
 
function setActiveKey(event) { //active status keys mouse event
  event.target.classList.add("piano-key-active", "piano-key-active-pseudo");
}
 
function removeActiveKey(event) { //remove active status keys mouse event 
  event.target.classList.remove("piano-key-active", "piano-key-active-pseudo");
}
 
function playAudio (data) { //start function playAudio
  const audio = document.querySelector(`audio[data-note="${data}"]`);
  audio.currentTime = 0;
  audio.play();
}
 
function startKeyActive (event) { //mouseover and mouseout events for active status keys, pseudo and play audio
  if (event.target.classList.contains("piano-key")) {
    event.target.classList.add("piano-key-active", "piano-key-active-pseudo");
    const song = event.target.dataset.note;
    playAudio(song);
  }
  collectionPiano.forEach((el) => {
    el.addEventListener("mouseover", playAudio);
    el.addEventListener("mouseover", setActiveKey);
    el.addEventListener("mouseout", removeActiveKey);
  });
};
 
function stopKeyIActive () { //remove mouseover and mouseout events for active status keys, pseudo and play audio
  collectionPiano.forEach((el) => {
    el.classList.remove("piano-key-active", "piano-key-active-pseudo");
    el.removeEventListener("mouseover", playAudio);
    el.removeEventListener("mouseover", setActiveKey);
    el.removeEventListener("mouseout", removeActiveKey);
  });
};
 
piano.addEventListener("mousedown", startKeyActive, playAudio);
document.addEventListener("mouseup", stopKeyIActive);
 
 
window.addEventListener("keydown", (event) => { // Event keyboard - play audio
  if (event.repeat) {
    return;
  } 
  const audioKeys = document.querySelector(`audio[data-key="${event.keyCode}"]`);
  const pianoKey = document.querySelector(`.piano-key[data-key="${event.keyCode}"]`);
  audioKeys.currentTime = 0;
  audioKeys.play(); 
  pianoKey.classList.add('piano-key-active');
 
  window.addEventListener("keyup", () => {
    pianoKey.classList.remove('piano-key-active');
  })
});

class Piano {
   state = {
     is_played: false,
     currentNote : false
   };
   piano  = document.querySelector(".piano_box");
   logBox = document.querySelector(".piano_log");
   
   constructor(name) {
    this.init();
  }
  
  log(msg) {
    //console.log(msg);
    this.logBox.innerHTML = msg + '<br>' + this.logBox.innerHTML;
  
  };
  
   startKeyActive (event) { //mouseover and mouseout events for active status keys, pseudo and play audio  
   let currentNote = event.target.dataset.note;
   if (app.state.is_played == false) {
       app.log("Пианино включено");
    } 
    if (currentNote == app.state.currentNote) {
       return;
    }
    
    app.state.currentNote = currentNote;
    app.state.is_played = true;
    
    app.log("Звучит нота " + app.state.currentNote);
  };
  
  moveKeyActive(event) {
    if (app.state.is_played) {
       app.startKeyActive.call(this, event);
    }
    
  }
  
  stopKeyActive () { //mouseover and mouseout events for active status keys, pseudo and play audio
    app.state.currentNote = false;
    app.state.is_played = false;
    
    app.log("Пианино выключено");
  };
  
  init() { 
     this.piano.addEventListener("mousedown", this.startKeyActive);
     this.piano.addEventListener("mousemove", this.moveKeyActive);
     this.piano.addEventListener("mouseup", this.stopKeyActive);
  }
  
 
}
 
var app = new Piano();

function playAudio (data) { //start function playAudio
  const audio = document.querySelector(`audio[data-note="${data}"]`);
  audio.currentTime = 0;
  audio.play();
}