Method updateScrollResize

src/utils.ts:590–609

* @internal Function used to scroll the page. * * @param event `MouseEvent` that triggers the resize * @param el `HTMLElement` that's being resized * @param distance Distance from the V edges to start scrolling

(event: MouseEvent, el: HTMLElement, distance: number)

   * @param distance Distance from the V edges to start scrolling
   */
  static updateScrollResize(event: MouseEvent, el: HTMLElement, distance: number): void {
    const scrollEl = Utils.getScrollElement(el);
    const height = scrollEl.clientHeight;
    // #1727 event.clientY is relative to viewport, so must compare this against position of scrollEl getBoundingClientRect().top
    // #1745 Special situation if scrollEl is document 'html': here browser spec states that
    // clientHeight is height of viewport, but getBoundingClientRect() is rectangle of html element;
    // this discrepancy arises because in reality scrollbar is attached to viewport, not html element itself.
    const offsetTop = (scrollEl === Utils.getScrollElement()) ? 0 : scrollEl.getBoundingClientRect().top;
    const pointerPosY = event.clientY - offsetTop;
    const top = pointerPosY < distance;
    const bottom = pointerPosY > height - distance;

    if (top) {
      // This also can be done with a timeout to keep scrolling while the mouse is
      // in the scrolling zone. (will have smoother behavior)
      scrollEl.scrollBy({ behavior: 'smooth', top: pointerPosY - distance});
    } else if (bottom) {
      scrollEl.scrollBy({ behavior: 'smooth', top: distance - (height - pointerPosY)});
    }
  }

  /** single level clone, returning a new object with same top fields. This will share sub objects and arrays */
  static clone<T>(obj: T): T {