React · Senior · Question 22 of 75

You need to render a list of 100,000 items. What should you do?

✓Correct answer: Virtualize: keep only the visible items in the DOM
2Wrap each item in memo and render everything at once
3Render items in batches of 1000 via setTimeout

Explanation

The bottleneck is the number of DOM nodes. Virtualization (TanStack Virtual, react-window) renders a window of visible rows and swaps them while scrolling. memo doesn't reduce the DOM, and timer batches only stretch out the same work. Also consider pagination or server-side filtering.

You need to render a list of 100,000 items. What should you do?

Explanation

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