add drag scrolling & improve code

packages/overlayscrollbars/src/setups/scrollbarsSetup/scrollbarsSetup.calculations.ts

@@ -0,0 +1,27 @@
+import type { StructureSetupState } from 'setups';
+
+const { min, max } = Math;
+export const getScrollbarHandleLengthRatio = (
+  structureSetupState: StructureSetupState,
+  isHorizontal?: boolean
+) => {
+  const { _overflowAmount, _overflowEdge } = structureSetupState;
+  const axis = isHorizontal ? 'x' : 'y';
+  const viewportSize = _overflowEdge[axis];
+  const overflowAmount = _overflowAmount[axis];
+  return max(0, min(1, viewportSize / (viewportSize + overflowAmount)));
+};
+export const getScrollbarHandleOffsetRatio = (
+  structureSetupState: StructureSetupState,
+  scrollOffsetElement: HTMLElement,
+  isHorizontal?: boolean
+) => {
+  const axis = isHorizontal ? 'x' : 'y';
+  const scrollLeftTop = isHorizontal ? 'Left' : 'Top';
+  const lengthRatio = getScrollbarHandleLengthRatio(structureSetupState, isHorizontal);
+  const scrollPosition = scrollOffsetElement[`scroll${scrollLeftTop}`] as number;
+  const scrollPositionMax = Math.floor(structureSetupState._overflowAmount[axis]);
+  const scrollPercent = min(1, scrollPosition / scrollPositionMax);
+
+  return (1 / lengthRatio) * (1 - lengthRatio) * scrollPercent;
+};

packages/overlayscrollbars/src/setups/scrollbarsSetup/scrollbarsSetup.elements.ts

@@ -3,15 +3,13 @@ import {
   appendChildren,
   createDiv,
   each,
+  isBoolean,
   isEmptyArray,
-  noop,
-  on,
   push,
   removeClass,
   removeElements,
   runEachAndClear,
   setT,
-  stopPropagation,
   style,
 } from 'support';
 import {
@@ -20,18 +18,18 @@ import {
   classNameScrollbarVertical,
   classNameScrollbarTrack,
   classNameScrollbarHandle,
-  classNamesScrollbarInteraction,
   classNamesScrollbarTransitionless,
 } from 'classnames';
 import { getEnvironment } from 'environment';
 import { dynamicInitializationElement as generalDynamicInitializationElement } from 'initialization';
 import type { InitializationTarget } from 'initialization';
 import type { StructureSetupElementsObj } from 'setups/structureSetup/structureSetup.elements';
+import type { ScrollbarsSetupEvents } from 'setups/scrollbarsSetup/scrollbarsSetup.events';
 import type {
   ScrollbarsInitialization,
   ScrollbarsDynamicInitializationElement,
 } from 'setups/scrollbarsSetup/scrollbarsSetup.initialization';
-import { StyleObject } from 'typings';
+import type { StyleObject } from 'typings';
 
 export interface ScrollbarStructure {
   _scrollbar: HTMLElement;
@@ -42,24 +40,19 @@ export interface ScrollbarStructure {
 export interface ScrollbarsSetupElement {
   _scrollbarStructures: ScrollbarStructure[];
   _clone: () => ScrollbarStructure;
-  _addRemoveClass: (
-    classNames: string | false | null | undefined,
-    add?: boolean,
-    elm?: (scrollbarStructure: ScrollbarStructure) => HTMLElement | false | null | undefined
-  ) => void;
   _handleStyle: (
     elmStyle: (
       scrollbarStructure: ScrollbarStructure
     ) => [HTMLElement | false | null | undefined, StyleObject]
   ) => void;
-  // _removeClass: (classNames: string) => void;
-  /*
-  _addEventListener: () => void;
-  _removeEventListener: () => void;
-  */
 }
 
 export interface ScrollbarsSetupElementsObj {
+  _scrollbarsAddRemoveClass: (
+    classNames: string | false | null | undefined,
+    add?: boolean,
+    isHorizontal?: boolean
+  ) => void;
   _horizontal: ScrollbarsSetupElement;
   _vertical: ScrollbarsSetupElement;
 }
@@ -70,23 +63,15 @@ export type ScrollbarsSetupElements = [
   destroy: () => void
 ];
 
-const interactionStartEventNames = 'touchstart mouseenter';
-const interactionEndEventNames = 'touchend touchcancel mouseleave';
-const stopRootClickPropagation = (scrollbar: HTMLElement, documentElm: Document) =>
-  on(
-    scrollbar,
-    'mousedown',
-    on.bind(0, documentElm, 'click', stopPropagation, { _once: true, _capture: true }),
-    { _capture: true }
-  );
-
 export const createScrollbarsSetupElements = (
   target: InitializationTarget,
-  structureSetupElements: StructureSetupElementsObj
+  structureSetupElements: StructureSetupElementsObj,
+  scrollbarsSetupEvents: ScrollbarsSetupEvents
 ): ScrollbarsSetupElements => {
   const { _getDefaultInitialization } = getEnvironment();
   const { scrollbarsSlot: defaultScrollbarsSlot } = _getDefaultInitialization();
-  const { _documentElm, _target, _host, _viewport, _targetIsElm } = structureSetupElements;
+  const { _documentElm, _target, _host, _viewport, _targetIsElm, _scrollOffsetElement } =
+    structureSetupElements;
   const { scrollbarsSlot } = (_targetIsElm ? {} : target) as ScrollbarsInitialization;
   const evaluatedScrollbarSlot =
     generalDynamicInitializationElement<ScrollbarsDynamicInitializationElement>(
@@ -95,15 +80,14 @@ export const createScrollbarsSetupElements = (
       defaultScrollbarsSlot,
       scrollbarsSlot
     );
-  const scrollbarsAddRemoveClass = (
+  const scrollbarStructureAddRemoveClass = (
     scrollbarStructures: ScrollbarStructure[],
     classNames: string | false | null | undefined,
-    add?: boolean,
-    elm?: (scrollbarStructure: ScrollbarStructure) => HTMLElement | false | null | undefined
+    add?: boolean
   ) => {
     const action = add ? addClass : removeClass;
     each(scrollbarStructures, (scrollbarStructure) => {
-      action((elm || noop)(scrollbarStructure) || scrollbarStructure._scrollbar, classNames);
+      action(scrollbarStructure._scrollbar, classNames);
     });
   };
   const scrollbarsHandleStyle = (
@@ -121,13 +105,22 @@ export const createScrollbarsSetupElements = (
   const horizontalScrollbars: ScrollbarStructure[] = [];
   const verticalScrollbars: ScrollbarStructure[] = [];
 
-  const addRemoveClassHorizontal = scrollbarsAddRemoveClass.bind(0, horizontalScrollbars);
-  const addRemoveClassVertical = scrollbarsAddRemoveClass.bind(0, verticalScrollbars);
-  const generateScrollbarDOM = (horizontal?: boolean): ScrollbarStructure => {
-    const scrollbarClassName = horizontal
+  const scrollbarsAddRemoveClass = (
+    className: string | false | null | undefined,
+    add?: boolean,
+    onlyHorizontal?: boolean
+  ) => {
+    const singleAxis = isBoolean(onlyHorizontal);
+    const runHorizontal = singleAxis ? onlyHorizontal : true;
+    const runVertical = singleAxis ? !onlyHorizontal : true;
+    runHorizontal && scrollbarStructureAddRemoveClass(horizontalScrollbars, className, add);
+    runVertical && scrollbarStructureAddRemoveClass(verticalScrollbars, className, add);
+  };
+  const generateScrollbarDOM = (isHorizontal?: boolean): ScrollbarStructure => {
+    const scrollbarClassName = isHorizontal
       ? classNameScrollbarHorizontal
       : classNameScrollbarVertical;
-    const arrToPush = horizontal ? horizontalScrollbars : verticalScrollbars;
+    const arrToPush = isHorizontal ? horizontalScrollbars : verticalScrollbars;
     const transitionlessClass = isEmptyArray(arrToPush) ? classNamesScrollbarTransitionless : '';
     const scrollbar = createDiv(
       `${classNameScrollbar} ${scrollbarClassName} ${transitionlessClass}`
@@ -146,15 +139,13 @@ export const createScrollbarsSetupElements = (
     push(arrToPush, result);
     push(destroyFns, [
       removeElements.bind(0, scrollbar),
-      on(scrollbar, interactionStartEventNames, () => {
-        addRemoveClassHorizontal(classNamesScrollbarInteraction, true);
-        addRemoveClassVertical(classNamesScrollbarInteraction, true);
-      }),
-      on(scrollbar, interactionEndEventNames, () => {
-        addRemoveClassHorizontal(classNamesScrollbarInteraction);
-        addRemoveClassVertical(classNamesScrollbarInteraction);
-      }),
-      stopRootClickPropagation(scrollbar, _documentElm),
+      scrollbarsSetupEvents(
+        result,
+        scrollbarsAddRemoveClass,
+        _documentElm,
+        _scrollOffsetElement,
+        isHorizontal
+      ),
     ]);
 
     return result;
@@ -166,8 +157,7 @@ export const createScrollbarsSetupElements = (
     appendChildren(evaluatedScrollbarSlot, verticalScrollbars[0]._scrollbar);
 
     setT(() => {
-      addRemoveClassHorizontal(classNamesScrollbarTransitionless);
-      addRemoveClassVertical(classNamesScrollbarTransitionless);
+      scrollbarsAddRemoveClass(classNamesScrollbarTransitionless);
     }, 300);
   };
 
@@ -176,16 +166,15 @@ export const createScrollbarsSetupElements = (
 
   return [
     {
+      _scrollbarsAddRemoveClass: scrollbarsAddRemoveClass,
       _horizontal: {
         _scrollbarStructures: horizontalScrollbars,
         _clone: generateHorizontalScrollbarStructure,
-        _addRemoveClass: addRemoveClassHorizontal,
         _handleStyle: scrollbarsHandleStyle.bind(0, horizontalScrollbars),
       },
       _vertical: {
         _scrollbarStructures: verticalScrollbars,
         _clone: generateVerticalScrollbarStructure,
-        _addRemoveClass: addRemoveClassVertical,
         _handleStyle: scrollbarsHandleStyle.bind(0, verticalScrollbars),
       },
     },

packages/overlayscrollbars/src/setups/scrollbarsSetup/scrollbarsSetup.events.ts

@@ -0,0 +1,116 @@
+import {
+  getBoundingClientRect,
+  offsetSize,
+  on,
+  preventDefault,
+  runEachAndClear,
+  stopPropagation,
+  XY,
+} from 'support';
+import { classNamesScrollbarInteraction } from 'classnames';
+import { getScrollbarHandleOffsetRatio } from 'setups/scrollbarsSetup/scrollbarsSetup.calculations';
+import type { StructureSetupState } from 'setups';
+import type {
+  ScrollbarsSetupElementsObj,
+  ScrollbarStructure,
+} from 'setups/scrollbarsSetup/scrollbarsSetup.elements';
+
+export type ScrollbarsSetupEvents = (
+  scrollbarStructure: ScrollbarStructure,
+  scrollbarsAddRemoveClass: ScrollbarsSetupElementsObj['_scrollbarsAddRemoveClass'],
+  documentElm: Document,
+  scrollOffsetElm: HTMLElement,
+  isHorizontal?: boolean
+) => () => void;
+
+const getPageOffset = (event: PointerEvent): XY<number> => ({
+  x: event.pageX,
+  y: event.pageY,
+});
+const getInvertedScale = (element: HTMLElement): XY<number> => {
+  const { width, height } = getBoundingClientRect(element);
+  const { w, h } = offsetSize(element);
+  return {
+    x: 1 / (Math.round(width) / w) || 1,
+    y: 1 / (Math.round(height) / h) || 1,
+  };
+};
+const createRootClickStopPropagationEvents = (scrollbar: HTMLElement, documentElm: Document) =>
+  on(
+    scrollbar,
+    'mousedown',
+    on.bind(0, documentElm, 'click', stopPropagation, { _once: true, _capture: true }),
+    { _capture: true }
+  );
+const createDragScrollingEvents = (
+  doc: Document,
+  scrollbarHandle: HTMLElement,
+  scrollOffsetElement: HTMLElement,
+  structureSetupState: () => StructureSetupState,
+  isHorizontal?: boolean
+) => {
+  const scrollOffsetKey = `scroll${isHorizontal ? 'Left' : 'Top'}`;
+  const xyKey = `${isHorizontal ? 'x' : 'y'}`;
+  const createOnPointerMoveHandler =
+    (mouseDownScroll: number, mouseDownPageOffset: number, mouseDownInvertedScale: number) =>
+    (event: PointerEvent) => {
+      const movement = (getPageOffset(event)[xyKey] - mouseDownPageOffset) * mouseDownInvertedScale;
+      const handleLengthRatio =
+        1 / getScrollbarHandleOffsetRatio(structureSetupState(), scrollOffsetElement, isHorizontal);
+      scrollOffsetElement[scrollOffsetKey] = mouseDownScroll + movement * handleLengthRatio;
+      // if (_isRTL && isHorizontal && !_rtlScrollBehavior.i) scrollDelta *= -1;
+    };
+
+  return on(scrollbarHandle, 'pointerdown', (pointerDownEvent: PointerEvent) => {
+    const { button, isPrimary, pointerId } = pointerDownEvent;
+
+    if (button === 0 && isPrimary) {
+      const mouseDownScroll = scrollOffsetElement[scrollOffsetKey] || 0;
+      const mouseDownPageOffset = getPageOffset(pointerDownEvent)[xyKey];
+      const mouseDownInvertedScale = getInvertedScale(scrollOffsetElement)[xyKey];
+      const offSelectStart = on(doc, 'selectstart', (event: Event) => preventDefault(event), {
+        _passive: false,
+      });
+      const offPointerMove = on(
+        scrollbarHandle,
+        'pointermove',
+        createOnPointerMoveHandler(mouseDownScroll, mouseDownPageOffset, mouseDownInvertedScale)
+      );
+
+      on(
+        scrollbarHandle,
+        'pointerup',
+        (pointerUpEvent: PointerEvent) => {
+          offSelectStart();
+          offPointerMove();
+          scrollbarHandle.releasePointerCapture(pointerUpEvent.pointerId);
+        },
+        { _once: true }
+      );
+      scrollbarHandle.setPointerCapture(pointerId);
+    }
+  });
+};
+
+export const createScrollbarsSetupEvents =
+  (structureSetupState: () => StructureSetupState): ScrollbarsSetupEvents =>
+  (scrollbarStructure, scrollbarsAddRemoveClass, documentElm, scrollOffsetElm, isHorizontal) => {
+    const { _scrollbar, _handle } = scrollbarStructure;
+
+    return runEachAndClear.bind(0, [
+      on(_scrollbar, 'pointerenter', () => {
+        scrollbarsAddRemoveClass(classNamesScrollbarInteraction, true);
+      }),
+      on(_scrollbar, 'pointerleave pointercancel', () => {
+        scrollbarsAddRemoveClass(classNamesScrollbarInteraction);
+      }),
+      createRootClickStopPropagationEvents(_scrollbar, documentElm),
+      createDragScrollingEvents(
+        documentElm,
+        _handle,
+        scrollOffsetElm,
+        structureSetupState,
+        isHorizontal
+      ),
+    ]);
+  };

packages/overlayscrollbars/src/setups/scrollbarsSetup/scrollbarsSetup.ts

@@ -11,6 +11,11 @@ import {
   scrollTop,
 } from 'support';
 import { createState, createOptionCheck } from 'setups/setups';
+import {
+  getScrollbarHandleLengthRatio,
+  getScrollbarHandleOffsetRatio,
+} from 'setups/scrollbarsSetup/scrollbarsSetup.calculations';
+import { createScrollbarsSetupEvents } from 'setups/scrollbarsSetup/scrollbarsSetup.events';
 import {
   createScrollbarsSetupElements,
   ScrollbarsSetupElement,
@@ -40,7 +45,6 @@ export interface ScrollbarsSetupStaticState {
   _appendElements: () => void;
 }
 
-const { min } = Math;
 const createSelfCancelTimeout = (timeout?: number | (() => number)) => {
   let id: number;
   const setTFn = timeout ? setT : rAF!;
@@ -55,17 +59,6 @@ const createSelfCancelTimeout = (timeout?: number | (() => number)) => {
   ] as [timeout: (callback: () => any) => void, clear: () => void];
 };
 
-const getScrollbarHandleRatio = (
-  structureSetupState: StructureSetupState,
-  isHorizontal?: boolean
-) => {
-  const { _overflowAmount, _overflowEdge } = structureSetupState;
-  const axis = isHorizontal ? 'x' : 'y';
-  const viewportSize = _overflowEdge[axis];
-  const overflowAmount = _overflowAmount[axis];
-  return min(1, viewportSize / (viewportSize + overflowAmount));
-};
-
 const refreshScrollbarHandleLength = (
   setStyleFn: ScrollbarsSetupElement['_handleStyle'],
   structureSetupState: StructureSetupState,
@@ -75,7 +68,7 @@ const refreshScrollbarHandleLength = (
     structure._handle,
     {
       [isHorizontal ? 'width' : 'height']: `${(
-        getScrollbarHandleRatio(structureSetupState, isHorizontal) * 100
+        getScrollbarHandleLengthRatio(structureSetupState, isHorizontal) * 100
       ).toFixed(3)}%`,
     },
   ]);
@@ -83,28 +76,23 @@ const refreshScrollbarHandleLength = (
 const refreshScrollbarHandleOffset = (
   setStyleFn: ScrollbarsSetupElement['_handleStyle'],
   structureSetupState: StructureSetupState,
-  viewport: HTMLElement,
+  scrollOffsetElement: HTMLElement,
   isHorizontal?: boolean
 ) => {
-  const axis = isHorizontal ? 'x' : 'y';
   const translateAxis = isHorizontal ? 'X' : 'Y';
-  const scrollLeftTop = isHorizontal ? 'Left' : 'Top';
-  const handleRatio = getScrollbarHandleRatio(structureSetupState, isHorizontal);
-  const scrollPosition = viewport[`scroll${scrollLeftTop}`] as number;
-  const scrollPositionMax =
-    (viewport[`scroll${scrollLeftTop}Max`] as number) ||
-    Math.floor(structureSetupState._overflowAmount[axis]);
+  const offsetRatio = getScrollbarHandleOffsetRatio(
+    structureSetupState,
+    scrollOffsetElement,
+    isHorizontal
+  );
+  // eslint-disable-next-line no-self-compare
+  const validOffsetRatio = offsetRatio === offsetRatio; // is false when offset is NaN
 
   setStyleFn((structure) => [
     structure._handle,
     {
-      transform: scrollPositionMax
-        ? `translate${translateAxis}(${(
-            (1 / handleRatio) *
-            (1 - handleRatio) *
-            (scrollPosition / scrollPositionMax) *
-            100
-          ).toFixed(3)}%)`
+      transform: validOffsetRatio
+        ? `translate${translateAxis}(${(offsetRatio * 100).toFixed(3)}%)`
         : '',
     },
   ]);
@@ -131,34 +119,38 @@ export const createScrollbarsSetup = (
   const [auotHideTimeout, clearAutoTimeout] = createSelfCancelTimeout(() => globalAutoHideDelay);
   const [elements, appendElements, destroyElements] = createScrollbarsSetupElements(
     target,
-    structureSetupState._elements
+    structureSetupState._elements,
+    createScrollbarsSetupEvents(structureSetupState)
   );
-  const { _host, _viewport, _viewportIsTarget, _isBody, _documentElm } =
-    structureSetupState._elements;
-  const scrollOffsetElement = _isBody ? _documentElm.documentElement : _viewport;
-  const { _horizontal, _vertical } = elements;
-  const { _addRemoveClass: addRemoveClassHorizontal, _handleStyle: styleHorizontal } = _horizontal;
-  const { _addRemoveClass: addRemoveClassVertical, _handleStyle: styleVertical } = _vertical;
+  const {
+    _host,
+    _viewport,
+    _scrollOffsetElement,
+    _scrollEventElement,
+    _viewportIsTarget,
+    _isBody,
+  } = structureSetupState._elements;
+  const { _horizontal, _vertical, _scrollbarsAddRemoveClass: scrollbarsAddRemoveClass } = elements;
+  const { _handleStyle: styleHorizontal } = _horizontal;
+  const { _handleStyle: styleVertical } = _vertical;
   const styleScrollbarPosition = (structure: ScrollbarStructure) => {
     const { _scrollbar } = structure;
     const elm = _viewportIsTarget && !_isBody && parent(_scrollbar) === _viewport && _scrollbar;
     return [
       elm,
       {
-        transform: elm ? `translate(${scrollLeft(_viewport)}px, ${scrollTop(_viewport)}px)` : '',
+        transform: elm
+          ? `translate(${scrollLeft(_scrollOffsetElement)}px, ${scrollTop(_scrollOffsetElement)}px)`
+          : '',
       },
     ] as [HTMLElement | false, StyleObject];
   };
   const manageScrollbarsAutoHide = (removeAutoHide: boolean, delayless?: boolean) => {
     clearAutoTimeout();
     if (removeAutoHide) {
-      addRemoveClassHorizontal(classNamesScrollbarAutoHidden);
-      addRemoveClassVertical(classNamesScrollbarAutoHidden);
+      scrollbarsAddRemoveClass(classNamesScrollbarAutoHidden);
     } else {
-      const hide = () => {
-        addRemoveClassHorizontal(classNamesScrollbarAutoHidden, true);
-        addRemoveClassVertical(classNamesScrollbarAutoHidden, true);
-      };
+      const hide = () => scrollbarsAddRemoveClass(classNamesScrollbarAutoHidden, true);
       if (globalAutoHideDelay > 0 && !delayless) {
         auotHideTimeout(hide);
       } else {
@@ -195,11 +187,11 @@ export const createScrollbarsSetup = (
           });
         });
     }),
-    on(_isBody ? _documentElm : _viewport, 'scroll', () => {
+    on(_scrollEventElement, 'scroll', () => {
       requestScrollAnimationFrame(() => {
         const structureState = structureSetupState();
-        refreshScrollbarHandleOffset(styleHorizontal, structureState, scrollOffsetElement, true);
-        refreshScrollbarHandleOffset(styleVertical, structureState, scrollOffsetElement);
+        refreshScrollbarHandleOffset(styleHorizontal, structureState, _scrollOffsetElement, true);
+        refreshScrollbarHandleOffset(styleVertical, structureState, _scrollOffsetElement);
 
         autoHideNotNever && manageScrollbarsAutoHide(true);
         scrollTimeout(() => {
@@ -237,13 +229,10 @@ export const createScrollbarsSetup = (
       const updateHandle = _overflowEdgeChanged || _overflowAmountChanged;
       const updateVisibility = _overflowStyleChanged || visibilityChanged;
 
-      const setScrollbarVisibility = (
-        overflowStyle: OverflowStyle,
-        addRemoveClass: (classNames: string, add?: boolean) => void
-      ) => {
+      const setScrollbarVisibility = (overflowStyle: OverflowStyle, isHorizontal: boolean) => {
         const isVisible =
           visibility === 'visible' || (visibility === 'auto' && overflowStyle === 'scroll');
-        addRemoveClass(classNamesScrollbarVisible, isVisible);
+        scrollbarsAddRemoveClass(classNamesScrollbarVisible, isVisible, isHorizontal);
         return isVisible;
       };
 
@@ -252,19 +241,16 @@ export const createScrollbarsSetup = (
       if (updateVisibility) {
         const { _overflowStyle } = currStructureSetupState;
 
-        const xVisible = setScrollbarVisibility(_overflowStyle.x, addRemoveClassHorizontal);
-        const yVisible = setScrollbarVisibility(_overflowStyle.y, addRemoveClassVertical);
+        const xVisible = setScrollbarVisibility(_overflowStyle.x, true);
+        const yVisible = setScrollbarVisibility(_overflowStyle.y, false);
         const hasCorner = xVisible && yVisible;
 
-        addRemoveClassHorizontal(classNamesScrollbarCornerless, !hasCorner);
-        addRemoveClassVertical(classNamesScrollbarCornerless, !hasCorner);
+        scrollbarsAddRemoveClass(classNamesScrollbarCornerless, !hasCorner);
       }
       if (themeChanged) {
-        addRemoveClassHorizontal(prevTheme);
-        addRemoveClassVertical(prevTheme);
+        scrollbarsAddRemoveClass(prevTheme);
+        scrollbarsAddRemoveClass(theme, true);
 
-        addRemoveClassHorizontal(theme, true);
-        addRemoveClassVertical(theme, true);
         prevTheme = theme;
       }
       if (autoHideChanged) {
@@ -280,10 +266,10 @@ export const createScrollbarsSetup = (
         refreshScrollbarHandleOffset(
           styleHorizontal,
           currStructureSetupState,
-          scrollOffsetElement,
+          _scrollOffsetElement,
           true
         );
-        refreshScrollbarHandleOffset(styleVertical, currStructureSetupState, scrollOffsetElement);
+        refreshScrollbarHandleOffset(styleVertical, currStructureSetupState, _scrollOffsetElement);
       }
     },
     scrollbarsSetupState,

packages/overlayscrollbars/src/setups/structureSetup/structureSetup.elements.ts

@@ -60,6 +60,8 @@ export interface StructureSetupElementsObj {
   _padding: HTMLElement | false;
   _content: HTMLElement | false;
   _viewportArrange: HTMLStyleElement | false | null | undefined;
+  _scrollOffsetElement: HTMLElement;
+  _scrollEventElement: HTMLElement | Document;
   // ctx ----
   _isTextarea: boolean;
   _isBody: boolean;
@@ -152,6 +154,8 @@ export const createStructureSetupElements = (
       !_nativeScrollbarsHiding &&
       createUniqueViewportArrangeElement &&
       createUniqueViewportArrangeElement(env),
+    _scrollOffsetElement: isBody ? ownerDocument.documentElement : viewportElement,
+    _scrollEventElement: isBody ? ownerDocument : viewportElement,
     _windowElm: wnd,
     _documentElm: ownerDocument,
     _isTextarea: isTextarea,

packages/overlayscrollbars/src/styles/scrollbars.scss

@@ -25,7 +25,7 @@ body > .os-scrollbar {
   border: none !important;
 }
 .os-scrollbar-handle {
-  pointer-events: none;
+  pointer-events: auto;
   position: absolute;
   width: 100%;
   height: 100%;
@@ -33,6 +33,7 @@ body > .os-scrollbar {
 .os-scrollbar-handle-interactive,
 .os-scrollbar-track-interactive {
   pointer-events: auto;
+  touch-action: none;
 }
 .os-scrollbar-unusable,
 .os-scrollbar-unusable * {