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
2.3 KiB
title, impact, impactDescription, tags
| title | impact | impactDescription | tags |
|---|---|---|---|
| Avoid Barrel File Imports | CRITICAL | 200-800ms import cost, slow builds | bundle, imports, tree-shaking, barrel-files, performance |
Avoid Barrel File Imports
Import directly from source files instead of barrel files to avoid loading thousands of unused modules. Barrel files are entry points that re-export multiple modules (e.g., index.js that does export * from './module').
Popular icon and component libraries can have up to 10,000 re-exports in their entry file. For many React packages, it takes 200-800ms just to import them, affecting both development speed and production cold starts.
Why tree-shaking doesn't help: When a library is marked as external (not bundled), the bundler can't optimize it. If you bundle it to enable tree-shaking, builds become substantially slower analyzing the entire module graph.
Incorrect (imports entire library):
import { Check, X, Menu } from 'lucide-react'
// Loads 1,583 modules, takes ~2.8s extra in dev
// Runtime cost: 200-800ms on every cold start
import { Button, TextField } from '@mui/material'
// Loads 2,225 modules, takes ~4.2s extra in dev
Correct (imports only what you need):
import Check from 'lucide-react/dist/esm/icons/check'
import X from 'lucide-react/dist/esm/icons/x'
import Menu from 'lucide-react/dist/esm/icons/menu'
// Loads only 3 modules (~2KB vs ~1MB)
import Button from '@mui/material/Button'
import TextField from '@mui/material/TextField'
// Loads only what you use
Alternative (Next.js 13.5+):
// next.config.js - use optimizePackageImports
module.exports = {
experimental: {
optimizePackageImports: ['lucide-react', '@mui/material']
}
}
// Then you can keep the ergonomic barrel imports:
import { Check, X, Menu } from 'lucide-react'
// Automatically transformed to direct imports at build time
Direct imports provide 15-70% faster dev boot, 28% faster builds, 40% faster cold starts, and significantly faster HMR.
Libraries commonly affected: lucide-react, @mui/material, @mui/icons-material, @tabler/icons-react, react-icons, @headlessui/react, @radix-ui/react-*, lodash, ramda, date-fns, rxjs, react-use.
Reference: How we optimized package imports in Next.js