.clearQueue()

https://api.jquery.com/clearQueue/

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>clearQueue demo</title>
  <style>
  div {
    margin: 3px;
    width: 40px;
    height: 40px;
    position: absolute;
    left: 0px;
    top: 30px;
    background: green;
    display: none;
  }
  div.newcolor {
    background: blue;
  }
  </style>
  <script src="https://code.jquery.com/jquery-3.7.0.js"></script>
</head>
<body>
 
<button id="start">Start</button>
<button id="stop">Stop</button>
<div></div>
 
<script>
$( "#start" ).on( "click", function() {
  var myDiv = $( "div" );
  myDiv.show( "slow" );
  myDiv.animate({
    left:"+=200"
  }, 5000 );
 
  myDiv.queue(function() {
    var that = $( this );
    that.addClass( "newcolor" );
    that.dequeue();
  });
 
  myDiv.animate({
    left:"-=200"
  }, 1500 );
  myDiv.queue(function() {
    var that = $( this );
    that.removeClass( "newcolor" );
    that.dequeue();
  });
  myDiv.slideUp();
});
 
$( "#stop" ).on( "click", function() {
  var myDiv = $( "div" );
  myDiv.clearQueue();
  myDiv.stop();
});
</script>
 
</body>
</html>

https://api.jquery.com/clearQueue/

<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>clearQueue demo</title>
<style>
div {
margin: 3px;
width: 40px;
height: 40px;
position: absolute;
left: 0px;
top: 30px;
background: green;
display: none;
}
div.newcolor {
background: blue;
}
</style>
<script src="https://code.jquery.com/jquery-3.7.0.js"></script>
</head>
<body>

<button id="start">Start</button>
<button id="stop">Stop</button>
<div></div>

<script>
$( "#start" ).on( "click", function() {
var myDiv = $( "div" );
myDiv.show( "slow" );
myDiv.animate({
left:"+=200"
}, 5000 );

myDiv.queue(function() {
var that = $( this );
that.addClass( "newcolor" );
that.dequeue();
});

myDiv.animate({
left:"-=200"
}, 1500 );
myDiv.queue(function() {
var that = $( this );
that.removeClass( "newcolor" );
that.dequeue();
});
myDiv.slideUp();
});

$( "#stop" ).on( "click", function() {
var myDiv = $( "div" );
myDiv.clearQueue();
myDiv.stop();
});
</script>

</body>
</html>