From afeac37bf0e3671d3353d416b507f9bd85781408 Mon Sep 17 00:00:00 2001 From: Karl Seamon Date: Tue, 1 Oct 2024 11:58:40 -0400 Subject: [PATCH] perf(cdk/table): Use ResizeObservers instead of dom measurement to reduce layout thrashing (where possible) --- src/cdk/table/sticky-styler.ts | 131 +++++++++++++++++++++++++++- tools/public_api_guard/cdk/table.md | 2 +- 2 files changed, 129 insertions(+), 4 deletions(-) diff --git a/src/cdk/table/sticky-styler.ts b/src/cdk/table/sticky-styler.ts index 144db5883cca..286cabacc6be 100644 --- a/src/cdk/table/sticky-styler.ts +++ b/src/cdk/table/sticky-styler.ts @@ -16,6 +16,12 @@ import {StickyPositioningListener} from './sticky-position-listener'; export type StickyDirection = 'top' | 'bottom' | 'left' | 'right'; +interface UpdateStickyColumnsParams { + rows: HTMLElement[]; + stickyStartStates: boolean[]; + stickyEndStates: boolean[]; +} + /** * List of all possible directions that can be used for sticky positioning. * @docs-private @@ -27,6 +33,12 @@ export const STICKY_DIRECTIONS: StickyDirection[] = ['top', 'bottom', 'left', 'r * @docs-private */ export class StickyStyler { + private _elemSizeCache = new WeakMap(); + private _resizeObserver = globalThis?.ResizeObserver + ? new globalThis.ResizeObserver(entries => this._updateCachedSizes(entries)) + : null; + private _updatedStickyColumnsParamsToReplay: UpdateStickyColumnsParams[] = []; + private _stickyColumnsReplayTimeout: number | null = null; private _cachedCellWidths: number[] = []; private readonly _borderCellCss: Readonly<{[d in StickyDirection]: string}>; @@ -68,6 +80,10 @@ export class StickyStyler { * @param stickyDirections The directions that should no longer be set as sticky on the rows. */ clearStickyPositioning(rows: HTMLElement[], stickyDirections: StickyDirection[]) { + if (stickyDirections.includes('left') || stickyDirections.includes('right')) { + this._removeFromStickyColumnReplayQueue(rows); + } + const elementsToClear: HTMLElement[] = []; for (const row of rows) { // If the row isn't an element (e.g. if it's an `ng-container`), @@ -100,13 +116,23 @@ export class StickyStyler { * in this index position should be stuck to the end of the row. * @param recalculateCellWidths Whether the sticky styler should recalculate the width of each * column cell. If `false` cached widths will be used instead. + * @param replay Whether to enqueue this call for replay after a ResizeObserver update. */ updateStickyColumns( rows: HTMLElement[], stickyStartStates: boolean[], stickyEndStates: boolean[], recalculateCellWidths = true, + replay = true, ) { + if (replay) { + this._updateStickyColumnReplayQueue({ + rows: [...rows], + stickyStartStates: [...stickyStartStates], + stickyEndStates: [...stickyEndStates], + }); + } + if ( !rows.length || !this._isBrowser || @@ -213,7 +239,7 @@ export class StickyStyler { ? (Array.from(row.children) as HTMLElement[]) : [row]; - const height = row.getBoundingClientRect().height; + const height = this._retrieveElementSize(row).height; stickyOffset += height; stickyCellHeights[rowIndex] = height; } @@ -366,8 +392,8 @@ export class StickyStyler { const cellWidths: number[] = []; const firstRowCells = row.children; for (let i = 0; i < firstRowCells.length; i++) { - let cell: HTMLElement = firstRowCells[i] as HTMLElement; - cellWidths.push(cell.getBoundingClientRect().width); + const cell = firstRowCells[i] as HTMLElement; + cellWidths.push(this._retrieveElementSize(cell).width); } this._cachedCellWidths = cellWidths; @@ -411,4 +437,103 @@ export class StickyStyler { return positions; } + + /** + * Retreives the most recently observed size of the specified element from the cache, or + * meaures it directly if not yet cached. + */ + private _retrieveElementSize(element: HTMLElement): {width: number; height: number} { + const cachedSize = this._elemSizeCache.get(element); + if (cachedSize) { + return cachedSize; + } + + const clientRect = element.getBoundingClientRect(); + const size = {width: clientRect.width, height: clientRect.height}; + + if (!this._resizeObserver) { + return size; + } + + this._elemSizeCache.set(element, size); + this._resizeObserver.observe(element, {box: 'border-box'}); + return size; + } + + /** + * Conditionally enqueue the requested sticky update and clear previously queued updates + * for the same rows. + */ + private _updateStickyColumnReplayQueue(params: UpdateStickyColumnsParams) { + this._removeFromStickyColumnReplayQueue(params.rows); + + // No need to replay if a flush is pending. + if (this._stickyColumnsReplayTimeout) { + return; + } + + this._updatedStickyColumnsParamsToReplay.push(params); + } + + /** Remove updates for the specified rows from the queue. */ + private _removeFromStickyColumnReplayQueue(rows: HTMLElement[]) { + const rowsSet = new Set(rows); + for (const update of this._updatedStickyColumnsParamsToReplay) { + update.rows = update.rows.filter(row => !rowsSet.has(row)); + } + this._updatedStickyColumnsParamsToReplay = this._updatedStickyColumnsParamsToReplay.filter( + update => !!update.rows.length, + ); + } + + /** Update _elemSizeCache with the observed sizes. */ + private _updateCachedSizes(entries: ResizeObserverEntry[]) { + let needsColumnUpdate = false; + for (const entry of entries) { + const newEntry = entry.borderBoxSize?.length + ? { + width: entry.borderBoxSize[0].inlineSize, + height: entry.borderBoxSize[0].blockSize, + } + : { + width: entry.contentRect.width, + height: entry.contentRect.height, + }; + + if ( + newEntry.width !== this._elemSizeCache.get(entry.target as HTMLElement)?.width && + isCell(entry.target) + ) { + needsColumnUpdate = true; + } + + this._elemSizeCache.set(entry.target as HTMLElement, newEntry); + } + + if (needsColumnUpdate && this._updatedStickyColumnsParamsToReplay.length) { + if (this._stickyColumnsReplayTimeout) { + clearTimeout(this._stickyColumnsReplayTimeout); + } + + this._stickyColumnsReplayTimeout = setTimeout(() => { + for (const update of this._updatedStickyColumnsParamsToReplay) { + this.updateStickyColumns( + update.rows, + update.stickyStartStates, + update.stickyEndStates, + true, + false, + ); + } + this._updatedStickyColumnsParamsToReplay = []; + this._stickyColumnsReplayTimeout = null; + }, 0); + } + } +} + +function isCell(element: Element) { + return ['cdk-cell', 'cdk-header-cell', 'cdk-footer-cell'].some(klass => + element.classList.contains(klass), + ); } diff --git a/tools/public_api_guard/cdk/table.md b/tools/public_api_guard/cdk/table.md index ed881068621e..2d07264d3f22 100644 --- a/tools/public_api_guard/cdk/table.md +++ b/tools/public_api_guard/cdk/table.md @@ -565,7 +565,7 @@ export class StickyStyler { _getStickyStartColumnPositions(widths: number[], stickyStates: boolean[]): number[]; _removeStickyStyle(element: HTMLElement, stickyDirections: StickyDirection[]): void; stickRows(rowsToStick: HTMLElement[], stickyStates: boolean[], position: 'top' | 'bottom'): void; - updateStickyColumns(rows: HTMLElement[], stickyStartStates: boolean[], stickyEndStates: boolean[], recalculateCellWidths?: boolean): void; + updateStickyColumns(rows: HTMLElement[], stickyStartStates: boolean[], stickyEndStates: boolean[], recalculateCellWidths?: boolean, replay?: boolean): void; updateStickyFooterContainer(tableElement: Element, stickyStates: boolean[]): void; }