update will sync observers, updated only called if something changed

packages/overlayscrollbars/src/observers/domObserver.ts

@@ -66,7 +66,10 @@ export type DOMObserverOptions<ContentObserver extends boolean> = ContentObserve
   ? DOMContentObserverOptions
   : DOMTargetObserverOptions;
 
-export type DOMObserver = [destroy: () => void, update: () => void];
+export type DOMObserver<ContentObserver extends boolean> = [
+  destroy: () => void,
+  update: () => void | false | Parameters<DOMObserverCallback<ContentObserver>>
+];
 
 type EventContentChangeUpdateElement = (getElements?: (selector: string) => Node[]) => void;
 type EventContentChange = [destroy: () => void, updateElements: EventContentChangeUpdateElement];
@@ -156,7 +159,7 @@ export const createDOMObserver = <ContentObserver extends boolean>(
   isContentObserver: ContentObserver,
   callback: DOMObserverCallback<ContentObserver>,
   options?: DOMObserverOptions<ContentObserver>
-): DOMObserver => {
+): DOMObserver<ContentObserver> => {
   let isConnected = false;
   const {
     _attributes,
@@ -166,16 +169,17 @@ export const createDOMObserver = <ContentObserver extends boolean>(
     _ignoreTargetChange,
     _ignoreContentChange,
   } = (options as DOMContentObserverOptions & DOMTargetObserverOptions) || {};
+  const debouncedEventContentChange = debounce(
+    () => {
+      if (isConnected) {
+        (callback as DOMContentObserverCallback)(true);
+      }
+    },
+    { _timeout: 33, _maxDelay: 99 }
+  );
   const [destroyEventContentChange, updateEventContentChangeElements] = createEventContentChange(
     target,
-    debounce(
-      () => {
-        if (isConnected) {
-          (callback as DOMContentObserverCallback)(true);
-        }
-      },
-      { _timeout: 33, _maxDelay: 99 }
-    ),
+    debouncedEventContentChange,
     _eventContentChange
   );
 
@@ -183,7 +187,10 @@ export const createDOMObserver = <ContentObserver extends boolean>(
   const finalAttributes = _attributes || [];
   const finalStyleChangingAttributes = _styleChangingAttributes || [];
   const observedAttributes = finalAttributes.concat(finalStyleChangingAttributes);
-  const observerCallback = (mutations: MutationRecord[]) => {
+  const observerCallback = (
+    mutations: MutationRecord[],
+    fromRecords?: true
+  ): void | Parameters<DOMObserverCallback<ContentObserver>> => {
     const ignoreTargetChange = _ignoreTargetChange || noop;
     const ignoreContentChange = _ignoreContentChange || noop;
     const targetChangedAttrs: string[] = [];
@@ -244,12 +251,20 @@ export const createDOMObserver = <ContentObserver extends boolean>(
     }
 
     if (isContentObserver) {
-      contentChanged && (callback as DOMContentObserverCallback)(false);
-    } else if (!isEmptyArray(targetChangedAttrs) || targetStyleChanged) {
-      (callback as DOMTargetObserverCallback)(targetChangedAttrs, targetStyleChanged);
+      !fromRecords && contentChanged && (callback as DOMContentObserverCallback)(false);
+      return [false] as Parameters<DOMObserverCallback<ContentObserver>>;
+    }
+    if (!isEmptyArray(targetChangedAttrs) || targetStyleChanged) {
+      !fromRecords &&
+        (callback as DOMTargetObserverCallback)(targetChangedAttrs, targetStyleChanged);
+      return [targetChangedAttrs, targetStyleChanged] as Parameters<
+        DOMObserverCallback<ContentObserver>
+      >;
     }
   };
-  const mutationObserver: MutationObserver = new MutationObserverConstructor!(observerCallback);
+  const mutationObserver: MutationObserver = new MutationObserverConstructor!((mutations) =>
+    observerCallback(mutations)
+  );
 
   // Connect
   mutationObserver.observe(target, {
@@ -272,7 +287,10 @@ export const createDOMObserver = <ContentObserver extends boolean>(
     },
     () => {
       if (isConnected) {
-        observerCallback(mutationObserver.takeRecords());
+        debouncedEventContentChange._flush();
+
+        const records = mutationObserver.takeRecords();
+        return !isEmptyArray(records) && observerCallback(records, true);
       }
     },
   ];

packages/overlayscrollbars/src/observers/trinsicObserver.ts

@@ -13,7 +13,11 @@ import {
 import { createSizeObserver } from 'observers/sizeObserver';
 import { classNameTrinsicObserver } from 'classnames';
 
-export type DestroyTrinsicObserver = () => void;
+export type TrinsicObserverCallback = (heightIntrinsic: CacheValues<boolean>) => any;
+export type TrinsicObserver = [
+  destroy: () => void,
+  update: () => void | Parameters<TrinsicObserverCallback>
+];
 
 const isHeightIntrinsic = (ioEntryOrSize: IntersectionObserverEntry | WH<number>): boolean =>
   (ioEntryOrSize as WH<number>).h === 0 ||
@@ -28,39 +32,45 @@ const isHeightIntrinsic = (ioEntryOrSize: IntersectionObserverEntry | WH<number>
  */
 export const createTrinsicObserver = (
   target: HTMLElement,
-  onTrinsicChangedCallback: (heightIntrinsic: CacheValues<boolean>) => any
-): DestroyTrinsicObserver => {
+  onTrinsicChangedCallback: TrinsicObserverCallback
+): TrinsicObserver => {
+  let intersectionObserverInstance: undefined | IntersectionObserver;
   const trinsicObserver = createDiv(classNameTrinsicObserver);
   const offListeners: (() => void)[] = [];
   const [updateHeightIntrinsicCache] = createCache({
     _initialValue: false,
   });
-
   const triggerOnTrinsicChangedCallback = (
-    updateValue?: IntersectionObserverEntry | WH<number>
-  ) => {
+    updateValue?: IntersectionObserverEntry | WH<number>,
+    fromRecords?: true
+  ): void | Parameters<TrinsicObserverCallback> => {
     if (updateValue) {
       const heightIntrinsic = updateHeightIntrinsicCache(isHeightIntrinsic(updateValue));
       const [, heightIntrinsicChanged] = heightIntrinsic;
 
       if (heightIntrinsicChanged) {
-        onTrinsicChangedCallback(heightIntrinsic);
+        !fromRecords && onTrinsicChangedCallback(heightIntrinsic);
+        return [heightIntrinsic];
       }
     }
   };
+  const intersectionObserverCallback = (
+    entries: IntersectionObserverEntry[],
+    fromRecords?: true
+  ) => {
+    if (entries && entries.length > 0) {
+      return triggerOnTrinsicChangedCallback(entries.pop(), fromRecords);
+    }
+  };
 
   if (IntersectionObserverConstructor) {
-    const intersectionObserverInstance: IntersectionObserver = new IntersectionObserverConstructor(
-      (entries: IntersectionObserverEntry[]) => {
-        if (entries && entries.length > 0) {
-          triggerOnTrinsicChangedCallback(entries.pop());
-        }
-      },
+    intersectionObserverInstance = new IntersectionObserverConstructor(
+      (entries) => intersectionObserverCallback(entries),
       { root: target }
     );
     intersectionObserverInstance.observe(trinsicObserver);
     push(offListeners, () => {
-      intersectionObserverInstance.disconnect();
+      intersectionObserverInstance!.disconnect();
     });
   } else {
     const onSizeChanged = () => {
@@ -73,8 +83,15 @@ export const createTrinsicObserver = (
 
   prependChildren(target, trinsicObserver);
 
-  return () => {
-    runEachAndClear(offListeners);
-    removeElements(trinsicObserver);
-  };
+  return [
+    () => {
+      runEachAndClear(offListeners);
+      removeElements(trinsicObserver);
+    },
+    () => {
+      if (intersectionObserverInstance) {
+        return intersectionObserverCallback(intersectionObserverInstance.takeRecords(), true);
+      }
+    },
+  ];
 };

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

@@ -18,6 +18,8 @@ import {
   isFunction,
   ResizeObserverConstructor,
   closest,
+  assignDeep,
+  push,
 } from 'support';
 import { getEnvironment } from 'environment';
 import {
@@ -41,8 +43,9 @@ import type {
 export type StructureSetupObserversUpdate = (checkOption: SetupUpdateCheckOption) => void;
 
 export type StructureSetupObservers = [
-  updateObserverOptions: StructureSetupObserversUpdate,
-  destroy: () => void
+  destroy: () => void,
+  updateObservers: () => Partial<StructureSetupUpdateHints>,
+  updateObserversOptions: StructureSetupObserversUpdate
 ];
 
 type ExcludeFromTuple<T extends readonly any[], E> = T extends [infer F, ...infer R]
@@ -69,7 +72,7 @@ export const createStructureSetupObservers = (
 ): StructureSetupObservers => {
   let debounceTimeout: number | false | undefined;
   let debounceMaxDelay: number | false | undefined;
-  let contentMutationObserver: DOMObserver | undefined;
+  let contentMutationObserver: DOMObserver<true> | undefined;
   const [, setState] = state;
   const {
     _host,
@@ -134,10 +137,14 @@ export const createStructureSetupObservers = (
       }
     });
   };
-  const onTrinsicChanged = (heightIntrinsicCache: CacheValues<boolean>) => {
+  const onTrinsicChanged = (heightIntrinsicCache: CacheValues<boolean>, fromRecords?: true) => {
     const [heightIntrinsic, heightIntrinsicChanged] = heightIntrinsicCache;
+    const updateHints: Partial<StructureSetupUpdateHints> = {
+      _heightIntrinsicChanged: heightIntrinsicChanged,
+    };
     setState({ _heightIntrinsic: heightIntrinsic });
-    structureSetupUpdate({ _heightIntrinsicChanged: heightIntrinsicChanged });
+    !fromRecords && structureSetupUpdate(updateHints);
+    return updateHints;
   };
   const onSizeChanged = ({
     _sizeChanged,
@@ -158,30 +165,36 @@ export const createStructureSetupObservers = (
 
     updateFn({ _sizeChanged, _directionChanged: directionChanged });
   };
-  const onContentMutation = (contentChangedTroughEvent: boolean) => {
+  const onContentMutation = (contentChangedTroughEvent: boolean, fromRecords?: true) => {
     const [, contentSizeChanged] = updateContentSizeCache();
+    const updateHints: Partial<StructureSetupUpdateHints> = {
+      _contentMutation: contentSizeChanged,
+    };
     // if contentChangedTroughEvent is true its already debounced
     const updateFn = contentChangedTroughEvent
       ? structureSetupUpdate
       : structureSetupUpdateWithDebouncedAdaptiveUpdateHints;
 
     if (contentSizeChanged) {
-      updateFn({
-        _contentMutation: true,
-      });
+      !fromRecords && updateFn(updateHints);
     }
+    return updateHints;
   };
-  const onHostMutation = (targetChangedAttrs: string[], targetStyleChanged: boolean) => {
+  const onHostMutation = (
+    targetChangedAttrs: string[],
+    targetStyleChanged: boolean,
+    fromRecords?: true
+  ) => {
+    const updateHints: Partial<StructureSetupUpdateHints> = { _hostMutation: targetStyleChanged };
     if (targetStyleChanged) {
-      structureSetupUpdateWithDebouncedAdaptiveUpdateHints({
-        _hostMutation: true,
-      });
+      !fromRecords && structureSetupUpdateWithDebouncedAdaptiveUpdateHints(updateHints);
     } else if (!_viewportIsTarget) {
       updateViewportAttrsFromHost(targetChangedAttrs);
     }
+    return updateHints;
   };
 
-  const destroyTrinsicObserver =
+  const trinsicObserver =
     (_content || !_flexboxGlue) && createTrinsicObserver(_host, onTrinsicChanged);
   const destroySizeObserver =
     !_viewportIsTarget &&
@@ -189,10 +202,15 @@ export const createStructureSetupObservers = (
       _appear: true,
       _direction: !_nativeScrollbarStyling,
     });
-  const [destroyHostMutationObserver] = createDOMObserver(_host, false, onHostMutation, {
-    _styleChangingAttributes: baseStyleChangingAttrs,
-    _attributes: baseStyleChangingAttrs.concat(viewportAttrsFromTarget),
-  });
+  const [destroyHostMutationObserver, updateHostMutationObserver] = createDOMObserver(
+    _host,
+    false,
+    onHostMutation,
+    {
+      _styleChangingAttributes: baseStyleChangingAttrs,
+      _attributes: baseStyleChangingAttrs.concat(viewportAttrsFromTarget),
+    }
+  );
 
   const viewportIsTargetResizeObserver =
     _viewportIsTarget &&
@@ -202,6 +220,58 @@ export const createStructureSetupObservers = (
   updateViewportAttrsFromHost();
 
   return [
+    () => {
+      contentMutationObserver && contentMutationObserver[0](); // destroy
+      trinsicObserver && trinsicObserver[0](); // destroy
+      destroySizeObserver && destroySizeObserver();
+      viewportIsTargetResizeObserver && viewportIsTargetResizeObserver.disconnect();
+      destroyHostMutationObserver();
+    },
+    () => {
+      const updateHints: Partial<StructureSetupUpdateHints> = {};
+      const hostUpdateResult = updateHostMutationObserver();
+      const contentUpdateResult = contentMutationObserver && contentMutationObserver[1](); // update
+      const trinsicUpdateResult = trinsicObserver && trinsicObserver[1](); // update
+
+      if (hostUpdateResult) {
+        assignDeep(
+          updateHints,
+          onHostMutation.apply(
+            0,
+            push(hostUpdateResult, true) as [
+              ...updateResult: typeof hostUpdateResult,
+              fromRecords: true
+            ]
+          )
+        );
+      }
+      if (contentUpdateResult) {
+        assignDeep(
+          updateHints,
+          onContentMutation.apply(
+            0,
+            push(contentUpdateResult, true) as [
+              ...updateResult: typeof contentUpdateResult,
+              fromRecords: true
+            ]
+          )
+        );
+      }
+      if (trinsicUpdateResult) {
+        assignDeep(
+          updateHints,
+          onTrinsicChanged.apply(
+            0,
+            push(trinsicUpdateResult as any[], true) as [
+              ...updateResult: typeof trinsicUpdateResult,
+              fromRecords: true
+            ]
+          )
+        );
+      }
+
+      return updateHints;
+    },
     (checkOption) => {
       const [ignoreMutation] = checkOption<string[] | null>('updating.ignoreMutation');
       const [attributes, attributesChanged] = checkOption<string[] | null>('updating.attributes');
@@ -261,12 +331,5 @@ export const createStructureSetupObservers = (
         }
       }
     },
-    () => {
-      contentMutationObserver && contentMutationObserver[0](); // destroy
-      destroyTrinsicObserver && destroyTrinsicObserver();
-      destroySizeObserver && destroySizeObserver();
-      viewportIsTargetResizeObserver && viewportIsTargetResizeObserver.disconnect();
-      destroyHostMutationObserver();
-    },
   ];
 };

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

@@ -1,4 +1,4 @@
-import { createEventListenerHub } from 'support';
+import { createEventListenerHub, isEmptyObject, keys } from 'support';
 import { createState, createOptionCheck } from 'setups/setups';
 import { createStructureSetupElements } from 'setups/structureSetup/structureSetup.elements';
 import { createStructureSetupUpdate } from 'setups/structureSetup/structureSetup.update';
@@ -79,11 +79,22 @@ export const createStructureSetup = (
   const [getState] = state;
   const [elements, appendElements, destroyElements] = createStructureSetupElements(target);
   const updateStructure = createStructureSetupUpdate(elements, state);
-  const [updateObservers, destroyObservers] = createStructureSetupObservers(
+  const triggerUpdateEvent: (...args: StructureSetupEventMap['u']) => void = (
+    updateHints,
+    changedOptions,
+    force
+  ) => {
+    const truthyUpdateHints = keys(updateHints).some((key) => updateHints[key]);
+
+    if (truthyUpdateHints || !isEmptyObject(changedOptions) || force) {
+      triggerEvent('u', [updateHints, changedOptions, force]);
+    }
+  };
+  const [destroyObservers, updateObservers, updateObserversOptions] = createStructureSetupObservers(
     elements,
     state,
     (updateHints) => {
-      triggerEvent('u', [updateStructure(checkOptionsFallback, updateHints), {}, false]);
+      triggerUpdateEvent(updateStructure(checkOptionsFallback, updateHints), {}, false);
     }
   );
 
@@ -98,8 +109,12 @@ export const createStructureSetup = (
   return [
     (changedOptions, force?) => {
       const checkOption = createOptionCheck(options, changedOptions, force);
-      updateObservers(checkOption);
-      triggerEvent('u', [updateStructure(checkOption, {}, force), changedOptions, !!force]);
+      updateObserversOptions(checkOption);
+      triggerUpdateEvent(
+        updateStructure(checkOption, updateObservers(), force),
+        changedOptions,
+        !!force
+      );
     },
     structureSetupState,
     () => {

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

@@ -29,7 +29,7 @@ const startBtn: HTMLButtonElement | null = document.querySelector('#start');
 const changesSlot: HTMLButtonElement | null = document.querySelector('#changes');
 const preInitChildren = targetElm?.children.length;
 
-const destroyTrinsicObserver = createTrinsicObserver(
+const [destroyTrinsicObserver, updateTrinsicObserver] = createTrinsicObserver(
   targetElm as HTMLElement,
   (heightIntrinsicCache) => {
     const [currentHeightIntrinsic, currentHeightIntrinsicChanged] = heightIntrinsicCache;
@@ -158,6 +158,9 @@ const start = async () => {
   });
   await changeWhileHidden();
 
+  updateTrinsicObserver();
+  destroyTrinsicObserver();
+  updateTrinsicObserver();
   destroyTrinsicObserver();
   should.equal(
     targetElm?.children.length,