qcast-front/.agents/skills/vercel-react-best-practices/rules/bundle-dynamic-imports.md

---
title: Dynamic Imports for Heavy Components
impact: CRITICAL
impactDescription: directly affects TTI and LCP
tags: bundle, dynamic-import, code-splitting, next-dynamic
---

## Dynamic Imports for Heavy Components

Use `next/dynamic` to lazy-load large components not needed on initial render.

**Incorrect (Monaco bundles with main chunk ~300KB):**

```tsx
import { MonacoEditor } from './monaco-editor'

function CodePanel({ code }: { code: string }) {
  return <MonacoEditor value={code} />
}
```

**Correct (Monaco loads on demand):**

```tsx
import dynamic from 'next/dynamic'

const MonacoEditor = dynamic(
  () => import('./monaco-editor').then(m => m.MonacoEditor),
  { ssr: false }
)

function CodePanel({ code }: { code: string }) {
  return <MonacoEditor value={code} />
}
```