mirror of
https://github.com/kjanat/livedash-node.git
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Kaj Kowalski
5bfd762e55
- Update tsconfig to ES2024 target and bundler moduleResolution - Add dynamic imports for chart.js and recharts (bundle optimization) - Consolidate 17 useState into useReducer in sessions page - Fix 18 .js extension imports across lib files - Add type declarations for @rapideditor/country-coder - Fix platform user types (PlatformUserRole enum) - Fix Calendar component prop types - Centralize next-auth type augmentation - Add force-dynamic to all API routes (prevent build-time prerender) - Fix Prisma JSON null handling with Prisma.DbNull - Fix various type mismatches (SessionMessage, ImportRecord, etc.) - Export ButtonProps from button component - Update next-themes import path - Replace JSX.Element with React.ReactElement - Remove obsolete debug scripts and pnpm lockfile - Downgrade eslint to v8 for next compatibility
38 lines
837 B
Markdown
38 lines
837 B
Markdown
---
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title: Build Index Maps for Repeated Lookups
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impact: LOW-MEDIUM
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impactDescription: 1M ops to 2K ops
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tags: javascript, map, indexing, optimization, performance
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---
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## Build Index Maps for Repeated Lookups
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Multiple `.find()` calls by the same key should use a Map.
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**Incorrect (O(n) per lookup):**
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```typescript
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function processOrders(orders: Order[], users: User[]) {
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return orders.map(order => ({
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...order,
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user: users.find(u => u.id === order.userId)
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}))
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}
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```
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**Correct (O(1) per lookup):**
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```typescript
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function processOrders(orders: Order[], users: User[]) {
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const userById = new Map(users.map(u => [u.id, u]))
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return orders.map(order => ({
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...order,
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user: userById.get(order.userId)
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}))
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}
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```
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Build map once (O(n)), then all lookups are O(1).
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For 1000 orders × 1000 users: 1M ops → 2K ops.
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