direction observer performance improvements, cache new feature and typing improvements

packages/overlayscrollbars/src/observers/domObserver.ts

@@ -16,26 +16,24 @@ import {
   isFunction,
 } from 'support';
 
-type TruthyOrFalsy = boolean | '' | 0 | null | undefined;
 type StringNullUndefined = string | null | undefined;
 export type DOMObserverEventContentChange =
   | Array<[StringNullUndefined, ((elms: Node[]) => string) | StringNullUndefined] | null | undefined>
   | false
-  | ''
   | null
   | undefined;
 export type DOMObserverIgnoreContentChange = (
   mutation: MutationRecord,
-  isNestedTarget: TruthyOrFalsy,
+  isNestedTarget: boolean,
   domObserverTarget: HTMLElement,
   domObserverOptions: DOMObserverOptions | undefined
-) => TruthyOrFalsy;
+) => boolean;
 export type DOMObserverIgnoreTargetAttrChange = (
   target: Node,
   attributeName: string,
   oldAttributeValue: string | null,
   newAttributeValue: string | null
-) => TruthyOrFalsy;
+) => boolean;
 export interface DOMObserverOptions {
   _observeContent?: boolean; // do observe children and trigger content change
   _attributes?: string[]; // observed attributes
@@ -190,7 +188,7 @@ export const createDOMObserver = (
         const baseAssertion = isNestedTarget
           ? !ignoreTargetChange(mutationTarget, attributeName!, oldValue, attributeValue as string | null)
           : notOnlyAttrChanged || contentAttrChanged;
-        const contentFinalChanged = baseAssertion && !ignoreContentChange(mutation, isNestedTarget, target, options);
+        const contentFinalChanged = baseAssertion && !ignoreContentChange(mutation, !!isNestedTarget, target, options);
 
         push(totalAddedNodes, addedNodes);
 

packages/overlayscrollbars/src/observers/sizeObserver.ts

@@ -14,12 +14,12 @@ import {
   preventDefault,
   stopPropagation,
   addClass,
-  isString,
   equalWH,
   push,
   cAF,
   rAF,
   ResizeObserverConstructor,
+  isArray,
 } from 'support';
 import { CSSDirection } from 'typings';
 import { getEnvironment } from 'environment';
@@ -36,28 +36,60 @@ const animationStartEventName = 'animationstart';
 const scrollEventName = 'scroll';
 const scrollAmount = 3333333;
 const getDirection = (elm: HTMLElement): CSSDirection => style(elm, 'direction') as CSSDirection;
+const domRectHasDimensions = (rect?: DOMRectReadOnly) => rect && (rect.height > 0 || rect.width > 0);
 
+interface SizeObserverEntry {
+  contentRect: DOMRectReadOnly;
+}
 export type SizeObserverOptions = { _direction?: boolean; _appear?: boolean };
 export const createSizeObserver = (
   target: HTMLElement,
   onSizeChangedCallback: (directionCache?: Cache<CSSDirection>) => any,
   options?: SizeObserverOptions
 ): (() => void) => {
-  const { _direction: direction = false, _appear: appear = false } = options || {};
+  const { _direction: observeDirectionChange = false, _appear: observeAppearChange = false } = options || {};
   const rtlScrollBehavior = getEnvironment()._rtlScrollBehavior;
   const baseElements = createDOM(`<div class="${classNameSizeObserver}"><div class="${classNameSizeObserverListener}"></div></div>`);
   const sizeObserver = baseElements[0] as HTMLElement;
   const listenerElement = sizeObserver.firstChild as HTMLElement;
-  const onSizeChangedCallbackProxy = (directionCache?: Cache<CSSDirection>) => {
-    if (direction) {
-      const rtl = getDirection(sizeObserver) === 'rtl';
+  const updateResizeObserverContentRectCache = createCache<DOMRectReadOnly, DOMRectReadOnly>(0, {
+    _alwaysUpdateValues: true,
+    _equal: (currVal, newVal) =>
+      !(
+        !currVal || // if no initial value
+        // if from display: none to display: block
+        (!domRectHasDimensions(currVal) && domRectHasDimensions(newVal))
+      ),
+  });
+  const onSizeChangedCallbackProxy = (sizeChangedContext?: Cache<CSSDirection> | SizeObserverEntry[] | Event) => {
+    const directionCacheValue = sizeChangedContext && (sizeChangedContext as Cache<CSSDirection>)._value;
+
+    let skip: boolean = false;
+    let doDirectionScroll = true; // always true if sizeChangedContext is Event
+
+    // if triggered from RO.
+    if (isArray(sizeChangedContext) && sizeChangedContext.length > 0) {
+      const { _previous, _value, _changed } = updateResizeObserverContentRectCache(0, sizeChangedContext.pop()!.contentRect);
+      skip = !_previous || !domRectHasDimensions(_value); // skip on initial RO. call or if display is none
+      doDirectionScroll = !skip && _changed; // direction scroll when not skipping and changing from display: none to block, false otherwise
+    }
+    // else if its triggered with DirectionCache
+    else if (directionCacheValue) {
+      doDirectionScroll = (sizeChangedContext as Cache<CSSDirection>)._changed; // direction scroll when DirectionCache changed, false toherwise
+    }
+
+    if (observeDirectionChange && doDirectionScroll) {
+      const rtl = (directionCacheValue || getDirection(sizeObserver)) === 'rtl';
       scrollLeft(sizeObserver, rtl ? (rtlScrollBehavior.n ? -scrollAmount : rtlScrollBehavior.i ? 0 : scrollAmount) : scrollAmount);
       scrollTop(sizeObserver, scrollAmount);
     }
-    onSizeChangedCallback(isString((directionCache || {})._value) ? directionCache : undefined);
+
+    if (!skip) {
+      onSizeChangedCallback(directionCacheValue ? (sizeChangedContext as Cache<CSSDirection>) : undefined);
+    }
   };
   const offListeners: (() => void)[] = [];
-  let appearCallback: ((...args: any) => any) | null = appear ? onSizeChangedCallbackProxy : null;
+  let appearCallback: ((...args: any) => any) | false = observeAppearChange ? onSizeChangedCallbackProxy : false;
 
   if (ResizeObserverConstructor) {
     const resizeObserverInstance = new ResizeObserverConstructor(onSizeChangedCallbackProxy);
@@ -120,10 +152,10 @@ export const createSizeObserver = (
       height: scrollAmount,
     });
     reset();
-    appearCallback = appear ? () => onScroll() : reset;
+    appearCallback = observeAppearChange ? () => onScroll() : reset;
   }
 
-  if (direction) {
+  if (observeDirectionChange) {
     const updateDirectionCache = createCache(() => getDirection(sizeObserver));
     push(
       offListeners,
@@ -152,7 +184,7 @@ export const createSizeObserver = (
     push(
       offListeners,
       on(sizeObserver, animationStartEventName, appearCallback, {
-        // Fire only once for "CSS is ready" event
+        // Fire only once for "CSS is ready" event if ResizeObserver strategy is used
         _once: !!ResizeObserverConstructor,
       })
     );

packages/overlayscrollbars/src/observers/trinsicObserver.ts

@@ -20,7 +20,7 @@ export const createTrinsicObserver = (
   const trinsicObserver = createDOM(`<div class="${classNameTrinsicObserver}"></div>`)[0] as HTMLElement;
   const offListeners: (() => void)[] = [];
   const updateHeightIntrinsicCache = createCache<boolean, IntersectionObserverEntry | WH<number>>(
-    (ioEntryOrSize) =>
+    (ioEntryOrSize: IntersectionObserverEntry | WH<number>) =>
       (ioEntryOrSize! as WH<number>).h === 0 ||
       (ioEntryOrSize! as IntersectionObserverEntry).isIntersecting ||
       (ioEntryOrSize! as IntersectionObserverEntry).intersectionRatio > 0,

packages/overlayscrollbars/src/support/cache/cache.ts

@@ -5,26 +5,38 @@ export interface Cache<T> {
 }
 
 export interface CacheOptions<T> {
+  // Custom comparison function if shallow compare isn't enough. Returns true if nothing changed.
   _equal?: EqualCachePropFunction<T>;
+  // Initial value for _value
   _initialValue?: T;
+  // If true updates always _value and _previous, otherwise they update only when changed
+  _alwaysUpdateValues?: boolean;
 }
 
-export type CacheUpdate<T, C> = (force?: boolean | 0, context?: C) => Cache<T>;
+export type CacheUpdate<T, C> = undefined extends C ? (force?: boolean | 0, context?: C) => Cache<T> : (force: boolean | 0, context: C) => Cache<T>;
 
-export type UpdateCachePropFunction<T, C> = (context?: C, current?: T, previous?: T) => T;
+export type UpdateCachePropFunction<T, C> = undefined extends C
+  ? (context?: C, current?: T, previous?: T) => T
+  : C extends T
+  ? ((context: C, current?: T, previous?: T) => T) | 0
+  : (context: C, current?: T, previous?: T) => T;
 
 export type EqualCachePropFunction<T> = (currentVal?: T, newVal?: T) => boolean;
 
 export const createCache = <T, C = undefined>(update: UpdateCachePropFunction<T, C>, options?: CacheOptions<T>): CacheUpdate<T, C> => {
-  const { _equal, _initialValue } = options || {};
+  const { _equal, _initialValue, _alwaysUpdateValues } = options || {};
   let _value: T | undefined = _initialValue;
   let _previous: T | undefined;
-  return (force, context) => {
+
+  const cacheUpdate = ((force?: boolean | 0, context?: C) => {
     const curr = _value;
-    const newVal = update(context, _value, _previous);
+    // @ts-ignore
+    // update can only not be a function if C extends T as described in "UpdateCachePropFunction" type definition
+    // if C extends T the cast (context as T) is perfectly valid
+    const newVal = update ? update(context, _value, _previous) : (context as T);
     const changed = force || (_equal ? !_equal(curr, newVal) : curr !== newVal);
 
-    if (changed) {
+    if (changed || _alwaysUpdateValues) {
       _value = newVal;
       _previous = curr;
     }
@@ -34,5 +46,7 @@ export const createCache = <T, C = undefined>(update: UpdateCachePropFunction<T,
       _previous,
       _changed: changed,
     };
-  };
+  }) as CacheUpdate<T, C>;
+
+  return cacheUpdate;
 };

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

@@ -3,7 +3,8 @@ import './index.scss';
 import should from 'should';
 import { generateClassChangeSelectCallback, iterateSelect } from '@/testing-browser/Select';
 import { setTestResult, waitForOrFailTest } from '@/testing-browser/TestResult';
-import { hasDimensions, offsetSize, WH, style, ResizeObserverConstructor } from 'support';
+import { timeout } from '@/testing-browser/timeout';
+import { hasDimensions, offsetSize, WH, style } from 'support';
 
 import { createSizeObserver } from 'observers/sizeObserver';
 
@@ -65,8 +66,7 @@ const iterate = async (select: HTMLSelectElement | null, afterEach?: () => any)
       const offsetSizeChanged = currOffsetSize.w !== newOffsetSize.w || currOffsetSize.h !== newOffsetSize.h;
       const contentSizeChanged = currContentSize.w !== newContentSize.w || currContentSize.h !== newContentSize.h;
       const dirChanged = currDir !== newDir;
-      // ResizeObserver Polyfill doesn't react on display: none, so make an exception there
-      const dimensions = ResizeObserverConstructor ? true : hasDimensions(targetElm as HTMLElement);
+      const dimensions = hasDimensions(targetElm as HTMLElement);
       const observerElm = targetElm?.firstElementChild as HTMLElement;
 
       // no overflow if not needed
@@ -87,6 +87,9 @@ const iterate = async (select: HTMLSelectElement | null, afterEach?: () => any)
           }
         });
       }
+      if (!dimensions) {
+        await timeout(100);
+      }
     },
     afterEach,
   });

packages/overlayscrollbars/tests/jsdom/support/cache/cache.test.ts

@@ -30,50 +30,88 @@ describe('cache', () => {
     expect(_changed).toBe(true);
   });
 
-  test('creates and updates cache with context', () => {
-    interface ContextObj {
-      test: string;
-      even: number;
-    }
-    const updateFn = jest.fn();
-    const updater = (context?: ContextObj, current?: boolean, previous?: boolean) => {
-      updateFn(context, current, previous);
-      return context!.test === 'test' || context!.even % 2 === 0;
-    };
-    const update = createCache(updater);
-    const firstCtx = { test: 'test', even: 2 };
+  describe('context', () => {
+    test('creates and updates cache with context', () => {
+      interface ContextObj {
+        test: string;
+        even: number;
+      }
+      const updateFn = jest.fn();
+      const updater = (context?: ContextObj, current?: boolean, previous?: boolean) => {
+        updateFn(context, current, previous);
+        return context!.test === 'test' || context!.even % 2 === 0;
+      };
+      const update = createCache(updater);
+      const firstCtx = { test: 'test', even: 2 };
 
-    let { _value, _previous, _changed } = update(0, firstCtx);
-    expect(updateFn).toHaveBeenLastCalledWith(firstCtx, undefined, undefined);
-    expect(_value).toBe(true);
-    expect(_previous).toBe(undefined);
-    expect(_changed).toBe(true);
+      let { _value, _previous, _changed } = update(0, firstCtx);
+      expect(updateFn).toHaveBeenLastCalledWith(firstCtx, undefined, undefined);
+      expect(_value).toBe(true);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(true);
 
-    ({ _value, _previous, _changed } = update(0, firstCtx));
-    expect(updateFn).toHaveBeenLastCalledWith(firstCtx, true, undefined);
-    expect(_value).toBe(true);
-    expect(_previous).toBe(undefined);
-    expect(_changed).toBe(false);
+      ({ _value, _previous, _changed } = update(0, firstCtx));
+      expect(updateFn).toHaveBeenLastCalledWith(firstCtx, true, undefined);
+      expect(_value).toBe(true);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(false);
 
-    const scndCtx = { test: 'nah', even: 1 };
+      const scndCtx = { test: 'nah', even: 1 };
 
-    ({ _value, _previous, _changed } = update(0, scndCtx));
-    expect(updateFn).toHaveBeenLastCalledWith(scndCtx, true, undefined);
-    expect(_value).toBe(false);
-    expect(_previous).toBe(true);
-    expect(_changed).toBe(true);
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(updateFn).toHaveBeenLastCalledWith(scndCtx, true, undefined);
+      expect(_value).toBe(false);
+      expect(_previous).toBe(true);
+      expect(_changed).toBe(true);
 
-    ({ _value, _previous, _changed } = update(0, scndCtx));
-    expect(updateFn).toHaveBeenLastCalledWith(scndCtx, false, true);
-    expect(_value).toBe(false);
-    expect(_previous).toBe(true);
-    expect(_changed).toBe(false);
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(updateFn).toHaveBeenLastCalledWith(scndCtx, false, true);
+      expect(_value).toBe(false);
+      expect(_previous).toBe(true);
+      expect(_changed).toBe(false);
 
-    ({ _value, _previous, _changed } = update(true, scndCtx));
-    expect(updateFn).toHaveBeenLastCalledWith(scndCtx, false, true);
-    expect(_value).toBe(false);
-    expect(_previous).toBe(false);
-    expect(_changed).toBe(true);
+      ({ _value, _previous, _changed } = update(true, scndCtx));
+      expect(updateFn).toHaveBeenLastCalledWith(scndCtx, false, true);
+      expect(_value).toBe(false);
+      expect(_previous).toBe(false);
+      expect(_changed).toBe(true);
+    });
+
+    test('creates and updates cache with context shorthand', () => {
+      interface ContextObj {
+        test: string;
+        even: number;
+      }
+      const update = createCache<ContextObj, ContextObj>(0);
+      const firstCtx = { test: 'test', even: 2 };
+
+      let { _value, _previous, _changed } = update(0, firstCtx);
+      expect(_value).toBe(firstCtx);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(true);
+
+      ({ _value, _previous, _changed } = update(0, firstCtx));
+      expect(_value).toBe(firstCtx);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(false);
+
+      const scndCtx = { test: 'nah', even: 1 };
+
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(firstCtx);
+      expect(_changed).toBe(true);
+
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(firstCtx);
+      expect(_changed).toBe(false);
+
+      ({ _value, _previous, _changed } = update(true, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(scndCtx);
+      expect(_changed).toBe(true);
+    });
   });
 
   describe('equal', () => {
@@ -131,7 +169,7 @@ describe('cache', () => {
   });
 
   describe('inital value', () => {
-    test('creates and updates cache with inital value', () => {
+    test('creates and updates cache with initialValue', () => {
       const [fn, updater] = createUpdater((i) => i);
       const update = createCache<number>(updater, { _initialValue: 0 });
 
@@ -148,7 +186,7 @@ describe('cache', () => {
       expect(_changed).toBe(true);
     });
 
-    test('creates and updates cache with inital value and equal', () => {
+    test('creates and updates cache with initialValue and equal', () => {
       const obj = { a: -1, b: -1 };
       const [fn, updater] = createUpdater((i) => ({ a: i, b: i + 1 }));
       const update = createCache<typeof obj>(updater, { _initialValue: obj, _equal: (a, b) => a?.a === b?.a && a?.b === b?.b });
@@ -167,6 +205,61 @@ describe('cache', () => {
     });
   });
 
+  describe('always update values', () => {
+    test('creates and updates cache with alwaysUpdateValues and equal always true', () => {
+      const [fn, updater] = createUpdater((i) => i);
+      const update = createCache<number>(updater, { _alwaysUpdateValues: true, _equal: () => true });
+
+      let { _value, _previous, _changed } = update();
+      expect(fn).toHaveBeenLastCalledWith(undefined, undefined, undefined);
+      expect(_value).toBe(1);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(false);
+
+      ({ _value, _previous, _changed } = update());
+      expect(fn).toHaveBeenLastCalledWith(undefined, 1, undefined);
+      expect(_value).toBe(2);
+      expect(_previous).toBe(1);
+      expect(_changed).toBe(false);
+    });
+
+    test('creates and updates cache with context shorthand and alwaysUpdateValues', () => {
+      interface ContextObj {
+        test: string;
+        even: number;
+      }
+      const update = createCache<ContextObj, ContextObj>(0, { _alwaysUpdateValues: true });
+      const firstCtx = { test: 'test', even: 2 };
+
+      let { _value, _previous, _changed } = update(0, firstCtx);
+      expect(_value).toBe(firstCtx);
+      expect(_previous).toBe(undefined);
+      expect(_changed).toBe(true);
+
+      ({ _value, _previous, _changed } = update(0, firstCtx));
+      expect(_value).toBe(firstCtx);
+      expect(_previous).toBe(firstCtx);
+      expect(_changed).toBe(false);
+
+      const scndCtx = { test: 'nah', even: 1 };
+
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(firstCtx);
+      expect(_changed).toBe(true);
+
+      ({ _value, _previous, _changed } = update(0, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(scndCtx);
+      expect(_changed).toBe(false);
+
+      ({ _value, _previous, _changed } = update(true, scndCtx));
+      expect(_value).toBe(scndCtx);
+      expect(_previous).toBe(scndCtx);
+      expect(_changed).toBe(true);
+    });
+  });
+
   describe('constant', () => {
     test('updates constant initially without intial value', () => {
       const [fn, updater] = createUpdater(() => true);