jc-timeline/src/utils/syncroScroll.ts

type scrollingDirection = "v" | "h" | "vh" | "hv" ; 

export default function syncronizeElementsScrolling(elements:Array<HTMLBaseElement>, direction:scrollingDirection = "vh"):void{
    let activeScroller:HTMLElement | null = null;
    const bSyncroV = direction.indexOf("v") > -1 ;
    const bSyncroH = direction.indexOf("h") > -1 ; 
    const applyListener = function(element:HTMLBaseElement) {
      element.addEventListener("mouseenter", function(e:MouseEvent) {
        activeScroller = e.target as HTMLElement;
      });
      element.addEventListener("scroll", function(e:Event) {
        if (e.target !== activeScroller) return;
        elements.forEach(function(element) {
          if (activeScroller === element || activeScroller === null) return;
          if (bSyncroV) element.scrollTop = activeScroller.scrollTop;
          if (bSyncroH) element.scrollLeft = activeScroller.scrollLeft;
        });
      });
    }
    elements.forEach(applyListener)
  }