Files
livedash-node/.github/skills/vercel-react-best-practices/rules/js-combine-iterations.md
Kaj Kowalski 5bfd762e55 fix: comprehensive TypeScript/build fixes and modernization
- 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
2026-01-20 07:28:10 +01:00

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Markdown

---
title: Combine Multiple Array Iterations
impact: LOW-MEDIUM
impactDescription: reduces iterations
tags: javascript, arrays, loops, performance
---
## Combine Multiple Array Iterations
Multiple `.filter()` or `.map()` calls iterate the array multiple times. Combine into one loop.
**Incorrect (3 iterations):**
```typescript
const admins = users.filter(u => u.isAdmin)
const testers = users.filter(u => u.isTester)
const inactive = users.filter(u => !u.isActive)
```
**Correct (1 iteration):**
```typescript
const admins: User[] = []
const testers: User[] = []
const inactive: User[] = []
for (const user of users) {
if (user.isAdmin) admins.push(user)
if (user.isTester) testers.push(user)
if (!user.isActive) inactive.push(user)
}
```