如何获得滚动移动的长度

var previousScrollPosition = window.scrollY;

window.addEventListener('scroll', function() {
  var currentScrollPosition = window.scrollY;
  var scrollDistance = currentScrollPosition - previousScrollPosition;
  console.log('滚动移动的长度：' + scrollDistance + '像素');
  previousScrollPosition = currentScrollPosition;
});

<style>
  .scroll-container {
    scroll-snap-type: y mandatory;
  }

  .scroll-item {
    scroll-snap-align: start;
  }
</style>

<div class="scroll-container">
  <div class="scroll-item">内容1</div>
  <div class="scroll-item">内容2</div>
  <div class="scroll-item">内容3</div>
</div>

<script>
  var scrollContainer = document.querySelector('.scroll-container');
  var previousScrollPosition = scrollContainer.scrollTop;

  scrollContainer.addEventListener('scroll', function() {
    var currentScrollPosition = scrollContainer.scrollTop;
    var scrollDistance = currentScrollPosition - previousScrollPosition;
    console.log('滚动移动的长度：' + scrollDistance + '像素');
    previousScrollPosition = currentScrollPosition;
  });
</script>