Refactor virtualization resize observer to track individual forOf elements. #16809
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projects/igniteui-angular-performance/src/app/hierarchical-grid/hierarchical-grid.component.ts
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rkaraivanov
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LGTM
I think we can squeeze out a little bit more perf with several of the points in this review.
| protected platformUtil = inject(PlatformUtil); | ||
| protected document = inject(DOCUMENT); | ||
| private _igxForOf: U & T[] | null = null; | ||
| protected _embeddedViewSizesCache = new Map<EmbeddedViewRef<any>, number>(); |
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| protected _embeddedViewSizesCache = new Map<EmbeddedViewRef<any>, number>(); | |
| protected _embeddedViewSizesCache = new WeakMap<EmbeddedViewRef<any>, number>(); |
I don't see the viewSizesCache being iterated, so let's go with the more memory-friendly version.
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| for (let index = 0; index < this._embeddedViews.length; index++) { | ||
| const targetIndex = this.state.startIndex + index; | ||
| const nodeSize = this.getEmbeddedViewSize(index); |
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getEmbeddedViewSize calls get embeddedViewNodes which creates a new array and iterates all views on each access to the getter. This is O(n²) operations at least. I suggest to cache the embeddedViewNodes outside the loop and adjust the calculations based on that.
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Can you drop the O(n) reduce operation?
Can you update the _virtSize with the totalDiff directly?
Something like:
this._virtSize += totalDiff;
if (this._virtSize > this._maxSize) {
this._virtRatio = this._virtSize / this._maxSize;
}
this.scrollComponent.size = Math.min(this.scrollComponent.size + totalDiff, this._maxSize);
if (!this.scrollComponent.destroyed) {
this.scrollComponent.cdr.detectChanges();
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| protected updateViewSizes(entries:ResizeObserverEntry[] ) { | ||
| entries.forEach((entry) => { | ||
| const index = parseInt(entry.target.getAttribute('data-index'), 0); |
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| const index = parseInt(entry.target.getAttribute('data-index'), 0); | |
| const index = parseInt(entry.target.getAttribute('data-index'), 10); |
A typo
| } | ||
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| protected updateViewSizes(entries:ResizeObserverEntry[] ) { | ||
| entries.forEach((entry) => { |
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Maybe a simple for of loop instead of a forEach?
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Closes #16821
Attach observer to individual root node views so that they track any change individually for that view. Update size accordingly.
Cache sizes of embedded views and use the cache when updating virtualization caches on scroll.
Additional information (check all that apply):
Checklist:
feature/README.MDupdates for the feature docsREADME.MDCHANGELOG.MDupdates for newly added functionalityng updatemigrations for the breaking changes (migrations guidelines)