Udit TakkarandGitHub
7a9fdd5a0c
## What does this PR do? This PR adds https://vercel.com/blog/introducing-react-best-practices for your coding agent using `npx add-skill vercel-labs/agent-skills` command The skills are added to `.claude/`, `.cursor/`, and `.opencode/` directories to provide React and Next.js performance optimization guidance for AI-assisted workflows. ## Updates since last revision Addressed Cubic AI review feedback for issues with confidence >= 9/10: - **rerender-dependencies.md** - Replaced `console.log(user.id)` with `fetchUserDetails(user.id)` to avoid logging sensitive information - **server-after-nonblocking.md** - Removed `sessionCookie` from `logUserAction` call to avoid logging sensitive authentication data, added `await` to async call - **bundle-conditional.md** - Added `loadError` state and `setLoadError` setter to fix undefined `setEnabled` reference - **advanced-event-handler-refs.md** - Updated `useWindowEvent` handler signature to accept `Event` parameter and forward it to the stored handler - **rerender-derived-state.md** - Closed `<nav>` elements in both examples for valid JSX Fixes applied to both `.claude` and `.cursor` skill directories for consistency. ## Mandatory Tasks (DO NOT REMOVE) - [x] I have self-reviewed the code (A decent size PR without self-review might be rejected). - [x] N/A I have updated the developer docs in /docs if this PR makes changes that would require a [documentation change](https://cal.com/docs). If N/A, write N/A here and check the checkbox. - [x] N/A, I confirm automated tests are in place that prove my fix is effective or that my feature works. ## How should this be tested? These are documentation files for AI coding agents. No runtime testing required - review the markdown files to verify the example code snippets are correct. ## Checklist for human review - [ ] Verify example code snippets in the skill files are syntactically correct - [ ] Confirm the fixes don't introduce new issues in the documentation examples - [ ] Check that `.claude` and `.cursor` directories have consistent content --- Link to Devin run: https://app.devin.ai/sessions/f7f7e67fdeea4b22a4817d63ed9e1759 Requested by: unknown ()
71 lines
1.6 KiB
Markdown
71 lines
1.6 KiB
Markdown
---
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title: Cache Storage API Calls
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impact: LOW-MEDIUM
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impactDescription: reduces expensive I/O
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tags: javascript, localStorage, storage, caching, performance
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---
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## Cache Storage API Calls
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`localStorage`, `sessionStorage`, and `document.cookie` are synchronous and expensive. Cache reads in memory.
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**Incorrect (reads storage on every call):**
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```typescript
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function getTheme() {
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return localStorage.getItem('theme') ?? 'light'
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}
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// Called 10 times = 10 storage reads
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```
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**Correct (Map cache):**
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```typescript
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const storageCache = new Map<string, string | null>()
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function getLocalStorage(key: string) {
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if (!storageCache.has(key)) {
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storageCache.set(key, localStorage.getItem(key))
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}
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return storageCache.get(key)
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}
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function setLocalStorage(key: string, value: string) {
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localStorage.setItem(key, value)
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storageCache.set(key, value) // keep cache in sync
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}
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```
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Use a Map (not a hook) so it works everywhere: utilities, event handlers, not just React components.
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**Cookie caching:**
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```typescript
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let cookieCache: Record<string, string> | null = null
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function getCookie(name: string) {
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if (!cookieCache) {
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cookieCache = Object.fromEntries(
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document.cookie.split('; ').map(c => c.split('='))
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)
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}
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return cookieCache[name]
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}
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```
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**Important (invalidate on external changes):**
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If storage can change externally (another tab, server-set cookies), invalidate cache:
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```typescript
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window.addEventListener('storage', (e) => {
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if (e.key) storageCache.delete(e.key)
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})
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document.addEventListener('visibilitychange', () => {
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if (document.visibilityState === 'visible') {
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storageCache.clear()
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}
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})
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```
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