ginnoir
3d825fba20
Adds the Vercel skill under .agents with famapp path patterns. Includes skills-lock.json pin.
41 lines
1.0 KiB
Markdown
41 lines
1.0 KiB
Markdown
---
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title: Use Transitions for Non-Urgent Updates
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impact: MEDIUM
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impactDescription: maintains UI responsiveness
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tags: rerender, transitions, startTransition, performance
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---
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## Use Transitions for Non-Urgent Updates
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Mark frequent, non-urgent state updates as transitions to maintain UI responsiveness.
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**Incorrect (blocks UI on every scroll):**
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```tsx
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function ScrollTracker() {
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const [scrollY, setScrollY] = useState(0);
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useEffect(() => {
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const handler = () => setScrollY(window.scrollY);
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window.addEventListener("scroll", handler, { passive: true });
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return () => window.removeEventListener("scroll", handler);
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}, []);
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}
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```
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**Correct (non-blocking updates):**
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```tsx
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import { startTransition } from "react";
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function ScrollTracker() {
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const [scrollY, setScrollY] = useState(0);
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useEffect(() => {
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const handler = () => {
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startTransition(() => setScrollY(window.scrollY));
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};
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window.addEventListener("scroll", handler, { passive: true });
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return () => window.removeEventListener("scroll", handler);
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}, []);
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}
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```
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