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]>
69 lines
1.6 KiB
Markdown
69 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(document.cookie.split('; ').map((c) => c.split('=')));
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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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