mirror of
https://github.com/kjanat/livedash-node.git
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Kaj Kowalski
cd05fc8648
- Fix syntax errors in skills markdown files (.github/skills, .opencode/skills) - Change typescript to tsx for code blocks with JSX - Replace ellipsis (...) in array examples with valid syntax - Separate CSS from TypeScript into distinct code blocks - Convert JavaScript object examples to valid JSON in docs - Fix enum definitions with proper comma separation
45 lines
1.1 KiB
Markdown
45 lines
1.1 KiB
Markdown
---
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title: Extract to Memoized Components
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impact: MEDIUM
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impactDescription: enables early returns
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tags: rerender, memo, useMemo, optimization
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---
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## Extract to Memoized Components
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Extract expensive work into memoized components to enable early returns before computation.
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**Incorrect (computes avatar even when loading):**
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```tsx
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function Profile({ user, loading }: Props) {
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const avatar = useMemo(() => {
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const id = computeAvatarId(user);
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return <Avatar id={id} />;
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}, [user]);
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if (loading) return <Skeleton />;
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return <div>{avatar}</div>;
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}
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```
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**Correct (skips computation when loading):**
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```tsx
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const UserAvatar = memo(function UserAvatar({ user }: { user: User }) {
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const id = useMemo(() => computeAvatarId(user), [user]);
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return <Avatar id={id} />;
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});
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function Profile({ user, loading }: Props) {
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if (loading) return <Skeleton />;
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return (
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<div>
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<UserAvatar user={user} />
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</div>
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);
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}
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```
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**Note:** If your project has [React Compiler](https://react.dev/learn/react-compiler) enabled, manual memoization with `memo()` and `useMemo()` is not necessary. The compiler automatically optimizes re-renders.
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