improve code

packages/overlayscrollbars/src/observers/sizeObserver.ts

@@ -38,7 +38,7 @@ export interface SizeObserverCallbackParams {
   _appear?: boolean;
 }
 
-export type DestroySizeObserver = () => void;
+export type SizeObserver = [destroy: () => void, append: () => void];
 
 const scrollAmount = 3333333;
 const getElmDirectionIsRTL = (elm: HTMLElement): boolean => style(elm, 'direction') === 'rtl';
@@ -55,7 +55,7 @@ export const createSizeObserver = (
   target: HTMLElement,
   onSizeChangedCallback: (params: SizeObserverCallbackParams) => any,
   options?: SizeObserverOptions
-): DestroySizeObserver => {
+): SizeObserver => {
   const { _direction: observeDirectionChange = false, _appear: observeAppearChange = false } =
     options || {};
   const sizeObserverPlugin = getPlugins()[sizeObserverPluginName] as
@@ -147,68 +147,71 @@ export const createSizeObserver = (
     : false;
   let directionIsRTLCache: Cache<boolean> | undefined;
 
-  if (ResizeObserverConstructor) {
-    const resizeObserverInstance = new ResizeObserverConstructor(onSizeChangedCallbackProxy);
-    resizeObserverInstance.observe(listenerElement);
-    push(offListeners, () => {
-      resizeObserverInstance.disconnect();
-    });
-  } else if (sizeObserverPlugin) {
-    const [pluginAppearCallback, pluginOffListeners] = sizeObserverPlugin._(
-      listenerElement,
-      onSizeChangedCallbackProxy,
-      observeAppearChange
-    );
-    appearCallback = pluginAppearCallback;
-    push(offListeners, pluginOffListeners);
-  }
+  return [
+    () => {
+      runEachAndClear(offListeners);
+      removeElements(sizeObserver);
+    },
+    () => {
+      if (ResizeObserverConstructor) {
+        const resizeObserverInstance = new ResizeObserverConstructor(onSizeChangedCallbackProxy);
+        resizeObserverInstance.observe(listenerElement);
+        push(offListeners, () => {
+          resizeObserverInstance.disconnect();
+        });
+      } else if (sizeObserverPlugin) {
+        const [pluginAppearCallback, pluginOffListeners] = sizeObserverPlugin._(
+          listenerElement,
+          onSizeChangedCallbackProxy,
+          observeAppearChange
+        );
+        appearCallback = pluginAppearCallback;
+        push(offListeners, pluginOffListeners);
+      }
 
-  if (observeDirectionChange) {
-    directionIsRTLCache = createCache(
-      {
-        _initialValue: !getIsDirectionRTL(), // invert current value to trigger initial change
-      },
-      getIsDirectionRTL
-    );
-    const [updateDirectionIsRTLCache] = directionIsRTLCache;
+      if (observeDirectionChange) {
+        directionIsRTLCache = createCache(
+          {
+            _initialValue: !getIsDirectionRTL(), // invert current value to trigger initial change
+          },
+          getIsDirectionRTL
+        );
+        const [updateDirectionIsRTLCache] = directionIsRTLCache;
 
-    push(
-      offListeners,
-      on(sizeObserver, 'scroll', (event: Event) => {
-        const directionIsRTLCacheValues = updateDirectionIsRTLCache();
-        const [directionIsRTL, directionIsRTLChanged] = directionIsRTLCacheValues;
+        push(
+          offListeners,
+          on(sizeObserver, 'scroll', (event: Event) => {
+            const directionIsRTLCacheValues = updateDirectionIsRTLCache();
+            const [directionIsRTL, directionIsRTLChanged] = directionIsRTLCacheValues;
 
-        if (directionIsRTLChanged) {
-          removeClass(listenerElement, 'ltr rtl');
-          if (directionIsRTL) {
-            addClass(listenerElement, 'rtl');
-          } else {
-            addClass(listenerElement, 'ltr');
-          }
-          onSizeChangedCallbackProxy(directionIsRTLCacheValues);
-        }
+            if (directionIsRTLChanged) {
+              removeClass(listenerElement, 'ltr rtl');
+              if (directionIsRTL) {
+                addClass(listenerElement, 'rtl');
+              } else {
+                addClass(listenerElement, 'ltr');
+              }
+              onSizeChangedCallbackProxy(directionIsRTLCacheValues);
+            }
 
-        stopPropagation(event);
-      })
-    );
-  }
+            stopPropagation(event);
+          })
+        );
+      }
 
-  // appearCallback is always needed on scroll-observer strategy to reset it
-  if (appearCallback) {
-    addClass(sizeObserver, classNameSizeObserverAppear);
-    push(
-      offListeners,
-      on(sizeObserver, 'animationstart', appearCallback, {
-        // Fire only once for "CSS is ready" event if ResizeObserver strategy is used
-        _once: !!ResizeObserverConstructor,
-      })
-    );
-  }
+      // appearCallback is always needed on scroll-observer strategy to reset it
+      if (appearCallback) {
+        addClass(sizeObserver, classNameSizeObserverAppear);
+        push(
+          offListeners,
+          on(sizeObserver, 'animationstart', appearCallback, {
+            // Fire only once for "CSS is ready" event if ResizeObserver strategy is used
+            _once: !!ResizeObserverConstructor,
+          })
+        );
+      }
 
-  prependChildren(target, sizeObserver);
-
-  return () => {
-    runEachAndClear(offListeners);
-    removeElements(sizeObserver);
-  };
+      prependChildren(target, sizeObserver);
+    },
+  ];
 };

packages/overlayscrollbars/src/observers/trinsicObserver.ts

@@ -16,6 +16,7 @@ import { classNameTrinsicObserver } from 'classnames';
 export type TrinsicObserverCallback = (heightIntrinsic: CacheValues<boolean>) => any;
 export type TrinsicObserver = [
   destroy: () => void,
+  append: () => void,
   update: () => void | Parameters<TrinsicObserverCallback>
 ];
 
@@ -63,31 +64,37 @@ export const createTrinsicObserver = (
     }
   };
 
-  if (IntersectionObserverConstructor) {
-    intersectionObserverInstance = new IntersectionObserverConstructor(
-      (entries) => intersectionObserverCallback(entries),
-      { root: target }
-    );
-    intersectionObserverInstance.observe(trinsicObserver);
-    push(offListeners, () => {
-      intersectionObserverInstance!.disconnect();
-    });
-  } else {
-    const onSizeChanged = () => {
-      const newSize = offsetSize(trinsicObserver);
-      triggerOnTrinsicChangedCallback(newSize);
-    };
-    push(offListeners, createSizeObserver(trinsicObserver, onSizeChanged));
-    onSizeChanged();
-  }
-
-  prependChildren(target, trinsicObserver);
-
   return [
     () => {
       runEachAndClear(offListeners);
       removeElements(trinsicObserver);
     },
+    () => {
+      if (IntersectionObserverConstructor) {
+        intersectionObserverInstance = new IntersectionObserverConstructor(
+          (entries) => intersectionObserverCallback(entries),
+          { root: target }
+        );
+        intersectionObserverInstance.observe(trinsicObserver);
+        push(offListeners, () => {
+          intersectionObserverInstance!.disconnect();
+        });
+      } else {
+        const onSizeChanged = () => {
+          const newSize = offsetSize(trinsicObserver);
+          triggerOnTrinsicChangedCallback(newSize);
+        };
+        const [destroySizeObserver, appendSizeObserver] = createSizeObserver(
+          trinsicObserver,
+          onSizeChanged
+        );
+        push(offListeners, destroySizeObserver);
+        appendSizeObserver();
+        onSizeChanged();
+      }
+
+      prependChildren(target, trinsicObserver);
+    },
     () => {
       if (intersectionObserverInstance) {
         return intersectionObserverCallback(intersectionObserverInstance.takeRecords(), true);

packages/overlayscrollbars/src/plugins/sizeObserverPlugin/sizeObserverPlugin.ts

@@ -91,7 +91,7 @@ export const sizeObserverPlugin: Plugin<SizeObserverPluginInstance> = {
         height: scrollAmount,
       });
 
-      reset();
+      rAF!(reset);
 
       return [observeAppearChange ? onScroll.bind(0, false) : reset, offListeners];
     },

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

@@ -1,7 +1,8 @@
 import { offsetSize } from 'support';
+import { getEnvironment } from 'environment';
 import type { StructureSetupState } from 'setups';
 
-const { min, max } = Math;
+const { min, max, abs } = Math;
 export const getScrollbarHandleLengthRatio = (
   scrollbarHandle: HTMLElement,
   scrollbarTrack: HTMLElement,
@@ -26,14 +27,22 @@ export const getScrollbarHandleOffsetRatio = (
   scrollbarTrack: HTMLElement,
   scrollOffsetElement: HTMLElement,
   structureSetupState: StructureSetupState,
+  isRTL: boolean,
   isHorizontal?: boolean
 ) => {
+  const { _rtlScrollBehavior } = getEnvironment();
   const axis = isHorizontal ? 'x' : 'y';
   const scrollLeftTop = isHorizontal ? 'Left' : 'Top';
   const { _overflowAmount } = structureSetupState;
-  const scrollPosition = scrollOffsetElement[`scroll${scrollLeftTop}`] as number;
   const scrollPositionMax = Math.floor(_overflowAmount[axis]);
-  const scrollPercent = min(1, scrollPosition / scrollPositionMax);
+  const scrollPosition = abs(scrollOffsetElement[`scroll${scrollLeftTop}`]);
+  const handleRTL = isHorizontal && isRTL;
+  const rtlNormalizedScrollPosition = _rtlScrollBehavior.i
+    ? scrollPosition
+    : scrollPositionMax - scrollPosition;
+  const finalScrollPosition = handleRTL ? rtlNormalizedScrollPosition : scrollPosition;
+  const scrollPercent = min(1, finalScrollPosition / scrollPositionMax);
   const lengthRatio = getScrollbarHandleLengthRatio(scrollbarHandle, scrollbarTrack, isHorizontal);
+
   return (1 / lengthRatio) * (1 - lengthRatio) * scrollPercent;
 };

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

@@ -132,12 +132,13 @@ export const createScrollbarsSetupElements = (
   ) => {
     const translateAxis = isHorizontal ? 'X' : 'Y';
     scrollbarsHandleStyle(scrollbarStructures, (structure) => {
-      const { _handle, _track } = structure;
+      const { _handle, _track, _scrollbar } = structure;
       const offsetRatio = getScrollbarHandleOffsetRatio(
         _handle,
         _track,
         _scrollOffsetElement,
         structureSetupState,
+        style(_scrollbar, 'direction') === 'rtl',
         isHorizontal
       );
       // eslint-disable-next-line no-self-compare

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

@@ -5,6 +5,7 @@ import {
   preventDefault,
   runEachAndClear,
   stopPropagation,
+  style,
   XY,
 } from 'support';
 import { classNamesScrollbarInteraction } from 'classnames';
@@ -14,6 +15,7 @@ import type {
   ScrollbarsSetupElementsObj,
   ScrollbarStructure,
 } from 'setups/scrollbarsSetup/scrollbarsSetup.elements';
+import { getEnvironment } from 'environment';
 
 export type ScrollbarsSetupEvents = (
   scrollbarStructure: ScrollbarStructure,
@@ -23,6 +25,7 @@ export type ScrollbarsSetupEvents = (
   isHorizontal?: boolean
 ) => () => void;
 
+const { round, abs } = Math;
 const getPageOffset = (event: PointerEvent): XY<number> => ({
   x: event.pageX,
   y: event.pageY,
@@ -31,8 +34,8 @@ const getScale = (element: HTMLElement): XY<number> => {
   const { width, height } = getBoundingClientRect(element);
   const { w, h } = offsetSize(element);
   return {
-    x: Math.round(width) / w || 1,
-    y: Math.round(height) / h || 1,
+    x: round(width) / w || 1,
+    y: round(height) / h || 1,
   };
 };
 const continuePointerDown = (
@@ -65,7 +68,8 @@ const createDragScrollingEvents = (
   structureSetupState: () => StructureSetupState,
   isHorizontal?: boolean
 ) => {
-  const { _handle, _track } = scrollbarStructure;
+  const { _rtlScrollBehavior } = getEnvironment();
+  const { _handle, _track, _scrollbar } = scrollbarStructure;
   const scrollOffsetKey = `scroll${isHorizontal ? 'Left' : 'Top'}`;
   const xyKey = `${isHorizontal ? 'x' : 'y'}`;
   const whKey = `${isHorizontal ? 'w' : 'h'}`;
@@ -77,9 +81,12 @@ const createDragScrollingEvents = (
       const handleTrackDiff = offsetSize(_track)[whKey] - offsetSize(_handle)[whKey];
       const scrollDeltaPercent = movement / handleTrackDiff;
       const scrollDelta = scrollDeltaPercent * _overflowAmount[xyKey];
+      const isRTL = style(_scrollbar, 'direction') === 'rtl';
+      const negateMultiplactor =
+        isRTL && isHorizontal ? (_rtlScrollBehavior.n || _rtlScrollBehavior.i ? 1 : -1) : 1;
 
-      scrollOffsetElement[scrollOffsetKey] = mouseDownScroll + scrollDelta;
-      // if (_isRTL && isHorizontal && !_rtlScrollBehavior.i) scrollDelta *= -1;
+      scrollOffsetElement[scrollOffsetKey] =
+        abs(mouseDownScroll) + scrollDelta * negateMultiplactor;
     };
 
   return on(_handle, 'pointerdown', (pointerDownEvent: PointerEvent) => {

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

@@ -173,8 +173,12 @@ export const createScrollbarsSetup = (
 
   return [
     (changedOptions, force, structureUpdateHints) => {
-      const { _overflowEdgeChanged, _overflowAmountChanged, _overflowStyleChanged } =
-        structureUpdateHints;
+      const {
+        _overflowEdgeChanged,
+        _overflowAmountChanged,
+        _overflowStyleChanged,
+        _directionChanged,
+      } = structureUpdateHints;
       const checkOption = createOptionCheck(options, changedOptions, force);
       const currStructureSetupState = structureSetupState();
       const { _overflowAmount, _overflowStyle } = currStructureSetupState;
@@ -187,7 +191,7 @@ export const createScrollbarsSetup = (
       const [dragScroll, dragScrollChanged] = checkOption<boolean>('scrollbars.dragScroll');
       const [clickScroll, clickScrollChanged] = checkOption<boolean>('scrollbars.clickScroll');
 
-      const updateHandle = _overflowEdgeChanged || _overflowAmountChanged;
+      const updateHandle = _overflowEdgeChanged || _overflowAmountChanged || _directionChanged;
       const updateVisibility = _overflowStyleChanged || visibilityChanged;
 
       const setScrollbarVisibility = (overflowStyle: OverflowStyle, isHorizontal: boolean) => {

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

@@ -22,6 +22,7 @@ import {
   push,
   scrollLeft,
   scrollTop,
+  noop,
 } from 'support';
 import { getEnvironment } from 'environment';
 import {
@@ -48,6 +49,7 @@ export type StructureSetupObserversUpdate = (checkOption: SetupUpdateCheckOption
 
 export type StructureSetupObservers = [
   destroy: () => void,
+  appendElements: () => void,
   updateObservers: () => Partial<StructureSetupUpdateHints>,
   updateObserversOptions: StructureSetupObserversUpdate
 ];
@@ -87,7 +89,7 @@ export const createStructureSetupObservers = (
     _viewportHasClass,
     _viewportAddRemoveClass,
   } = structureSetupElements;
-  const { _nativeScrollbarsHiding: _nativeScrollbarStyling, _flexboxGlue } = getEnvironment();
+  const { _flexboxGlue } = getEnvironment();
 
   const [updateContentSizeCache] = createCache<WH<number>>(
     {
@@ -207,14 +209,14 @@ export const createStructureSetupObservers = (
     return updateHints;
   };
 
-  const trinsicObserver =
-    (_content || !_flexboxGlue) && createTrinsicObserver(_host, onTrinsicChanged);
-  const destroySizeObserver =
-    !_viewportIsTarget &&
-    createSizeObserver(_host, onSizeChanged, {
-      _appear: true,
-      _direction: !_nativeScrollbarStyling,
-    });
+  const [destroyTrinsicObserver, appendTrinsicObserver, updateTrinsicObserver] =
+    _content || !_flexboxGlue ? createTrinsicObserver(_host, onTrinsicChanged) : [noop, noop, noop];
+  const [destroySizeObserver, appendSizeObserver] = !_viewportIsTarget
+    ? createSizeObserver(_host, onSizeChanged, {
+        _appear: true,
+        _direction: true,
+      })
+    : [noop, noop];
   const [destroyHostMutationObserver, updateHostMutationObserver] = createDOMObserver(
     _host,
     false,
@@ -235,17 +237,21 @@ export const createStructureSetupObservers = (
 
   return [
     () => {
+      destroyTrinsicObserver();
+      destroySizeObserver();
       contentMutationObserver && contentMutationObserver[0](); // destroy
-      trinsicObserver && trinsicObserver[0](); // destroy
-      destroySizeObserver && destroySizeObserver();
       viewportIsTargetResizeObserver && viewportIsTargetResizeObserver.disconnect();
       destroyHostMutationObserver();
     },
+    () => {
+      appendSizeObserver();
+      appendTrinsicObserver();
+    },
     () => {
       const updateHints: Partial<StructureSetupUpdateHints> = {};
       const hostUpdateResult = updateHostMutationObserver();
+      const trinsicUpdateResult = updateTrinsicObserver();
       const contentUpdateResult = contentMutationObserver && contentMutationObserver[1](); // update
-      const trinsicUpdateResult = trinsicObserver && trinsicObserver[1](); // update
 
       if (hostUpdateResult) {
         assignDeep(
@@ -259,18 +265,6 @@ export const createStructureSetupObservers = (
           )
         );
       }
-      if (contentUpdateResult) {
-        assignDeep(
-          updateHints,
-          onContentMutation.apply(
-            0,
-            push(contentUpdateResult, true) as [
-              ...updateResult: typeof contentUpdateResult,
-              fromRecords: true
-            ]
-          )
-        );
-      }
       if (trinsicUpdateResult) {
         assignDeep(
           updateHints,
@@ -283,6 +277,18 @@ export const createStructureSetupObservers = (
           )
         );
       }
+      if (contentUpdateResult) {
+        assignDeep(
+          updateHints,
+          onContentMutation.apply(
+            0,
+            push(contentUpdateResult, true) as [
+              ...updateResult: typeof contentUpdateResult,
+              fromRecords: true
+            ]
+          )
+        );
+      }
 
       return updateHints;
     },

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

@@ -73,7 +73,7 @@ export const createStructureSetup = (
   const state = createState(initialStructureSetupUpdateState);
   const [addEvent, removeEvent, triggerEvent] = createEventListenerHub<StructureSetupEventMap>();
   const [getState] = state;
-  const [elements, appendElements, destroyElements] = createStructureSetupElements(target);
+  const [elements, appendStructureElements, destroyElements] = createStructureSetupElements(target);
   const updateStructure = createStructureSetupUpdate(elements, state);
   const triggerUpdateEvent: (...args: StructureSetupEventMap['u']) => void = (
     updateHints,
@@ -86,20 +86,20 @@ export const createStructureSetup = (
       triggerEvent('u', [updateHints, changedOptions, force]);
     }
   };
-  const [destroyObservers, updateObservers, updateObserversOptions] = createStructureSetupObservers(
-    elements,
-    state,
-    (updateHints) => {
+  const [destroyObservers, appendObserverElements, updateObservers, updateObserversOptions] =
+    createStructureSetupObservers(elements, state, (updateHints) => {
       triggerUpdateEvent(updateStructure(checkOptionsFallback, updateHints), {}, false);
-    }
-  );
+    });
 
   const structureSetupState = getState.bind(0) as (() => StructureSetupState) &
     StructureSetupStaticState;
   structureSetupState._addOnUpdatedListener = (listener) => {
     addEvent('u', listener);
   };
-  structureSetupState._appendElements = appendElements;
+  structureSetupState._appendElements = () => {
+    appendStructureElements();
+    appendObserverElements();
+  };
   structureSetupState._elements = elements;
 
   return [

packages/overlayscrollbars/src/styles/scrollbars.scss

@@ -18,6 +18,7 @@ body > .os-scrollbar {
 }
 .os-scrollbar-track {
   position: relative;
+  direction: ltr !important;
   padding: 0 !important;
   border: none !important;
 }
@@ -31,7 +32,7 @@ body > .os-scrollbar {
   height: 100%;
 }
 .os-scrollbar.os-scrollbar-track-interactive .os-scrollbar-track,
-.os-scrollbar.os-scrollbar-handle-interactive .os-scrollbar-handle  {
+.os-scrollbar.os-scrollbar-handle-interactive .os-scrollbar-handle {
   pointer-events: auto;
   touch-action: none;
 }
@@ -61,10 +62,10 @@ body > .os-scrollbar {
 }
 .os-scrollbar-unusable,
 .os-scrollbar-unusable * {
-    pointer-events: none !important;
+  pointer-events: none !important;
 }
 .os-scrollbar-unusable .os-scrollbar-handle {
-    opacity: 0 !important;
+  opacity: 0 !important;
 }
 .os-scrollbar.os-scrollbar-horizontal.os-scrollbar-cornerless {
   left: 0;

packages/overlayscrollbars/src/styles/sizeobserver.scss

@@ -24,7 +24,7 @@ $shrink-scale: 0.1;
   z-index: -1;
   contain: strict;
   display: flex;
-  flex-direction: column;
+  flex-direction: row;
   flex-wrap: nowrap;
   padding: inherit;
   border: inherit;

packages/overlayscrollbars/tests/playwright/observers/sizeObserver/index.browser.ts

@@ -47,7 +47,7 @@ const startBtn: HTMLButtonElement | null = document.querySelector('#start');
 const resizesSlot: HTMLButtonElement | null = document.querySelector('#resizes');
 const preInitChildren = targetElm?.children.length;
 
-const destroySizeObserver = createSizeObserver(
+const [destroySizeObserver, appendSizeObserver] = createSizeObserver(
   targetElm as HTMLElement,
   ({ _directionIsRTLCache, _sizeChanged }) => {
     if (_sizeChanged) {
@@ -66,6 +66,7 @@ const destroySizeObserver = createSizeObserver(
   },
   { _direction: true, _appear: true }
 );
+appendSizeObserver();
 
 const selectCallback = generateClassChangeSelectCallback(targetElm as HTMLElement);
 const iterate = async (select: HTMLSelectElement | null, afterEach?: () => any) => {

packages/overlayscrollbars/tests/playwright/observers/trinsicObserver/index.browser.ts

@@ -29,9 +29,8 @@ const startBtn: HTMLButtonElement | null = document.querySelector('#start');
 const changesSlot: HTMLButtonElement | null = document.querySelector('#changes');
 const preInitChildren = targetElm?.children.length;
 
-const [destroyTrinsicObserver, updateTrinsicObserver] = createTrinsicObserver(
-  targetElm as HTMLElement,
-  (heightIntrinsicCache) => {
+const [destroyTrinsicObserver, appendTrinsicObserver, updateTrinsicObserver] =
+  createTrinsicObserver(targetElm as HTMLElement, (heightIntrinsicCache) => {
     const [currentHeightIntrinsic, currentHeightIntrinsicChanged] = heightIntrinsicCache;
     if (currentHeightIntrinsicChanged) {
       heightIterations += 1;
@@ -42,8 +41,8 @@ const [destroyTrinsicObserver, updateTrinsicObserver] = createTrinsicObserver(
         changesSlot.textContent = heightIterations.toString();
       }
     });
-  }
-);
+  });
+appendTrinsicObserver();
 
 const envElmSelectCallback = generateClassChangeSelectCallback(envElm as HTMLElement);
 const targetElmSelectCallback = generateClassChangeSelectCallback(targetElm as HTMLElement);

packages/overlayscrollbars/types/update.d.ts

@@ -0,0 +1 @@
+export {};