dcaaef1011
Format: YYYY-MM-DD-description.md - 2026-01-19-infrastructure-deployment.md - 2026-01-19-backend-api-implementation.md (in progress) Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>
39 lines
815 B
Markdown
39 lines
815 B
Markdown
---
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title: CSS content-visibility for Long Lists
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impact: HIGH
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impactDescription: faster initial render
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tags: rendering, css, content-visibility, long-lists
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---
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## CSS content-visibility for Long Lists
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Apply `content-visibility: auto` to defer off-screen rendering.
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**CSS:**
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```css
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.message-item {
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content-visibility: auto;
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contain-intrinsic-size: 0 80px;
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}
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```
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**Example:**
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```tsx
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function MessageList({ messages }: { messages: Message[] }) {
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return (
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<div className="overflow-y-auto h-screen">
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{messages.map(msg => (
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<div key={msg.id} className="message-item">
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<Avatar user={msg.author} />
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<div>{msg.content}</div>
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</div>
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))}
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</div>
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)
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}
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```
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For 1000 messages, browser skips layout/paint for ~990 off-screen items (10× faster initial render).
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