AngeloooooandDraculabo
8ed4593f73
* Refactor Gemini model display: filter old versions, group low/high pro, and improve naming * Fix potential negative minutes and refine Gemini 3 Pro grouping logic based on PR feedback * The account change process has been sped up * Address PR review: enhance error message and parameterize polling interval in process handler * Address PR review: fix potential race condition in database backup logic * fix: prevent renderer white screen and harden sentry gating * feat: localize model labels * chore: enable hoisted node-linker * chore: ignore .agent/.claude/.codex in prettier --------- Co-authored-by: Draculabo <[email protected]>
41 lines
1.2 KiB
Markdown
41 lines
1.2 KiB
Markdown
---
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title: Calculate Derived State During Rendering
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impact: MEDIUM
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impactDescription: avoids redundant renders and state drift
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tags: rerender, derived-state, useEffect, state
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---
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## Calculate Derived State During Rendering
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If a value can be computed from current props/state, do not store it in state or update it in an effect. Derive it during render to avoid extra renders and state drift. Do not set state in effects solely in response to prop changes; prefer derived values or keyed resets instead.
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**Incorrect (redundant state and effect):**
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```tsx
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function Form() {
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const [firstName, setFirstName] = useState('First');
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const [lastName, setLastName] = useState('Last');
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const [fullName, setFullName] = useState('');
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useEffect(() => {
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setFullName(firstName + ' ' + lastName);
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}, [firstName, lastName]);
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return <p>{fullName}</p>;
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}
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```
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**Correct (derive during render):**
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```tsx
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function Form() {
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const [firstName, setFirstName] = useState('First');
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const [lastName, setLastName] = useState('Last');
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const fullName = firstName + ' ' + lastName;
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return <p>{fullName}</p>;
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}
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```
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References: [You Might Not Need an Effect](https://react.dev/learn/you-might-not-need-an-effect)
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