gt-agent-company/.agents/skills/vite/references/features-dep-bundling.md

name, description

name	description
features-dep-bundling	Dependency pre-bundling configuration and caching

Dependency Pre-Bundling

Vite pre-bundles dependencies on first run for faster dev server startup.

Why Pre-Bundling

1. CommonJS/UMD to ESM - Convert non-ESM dependencies
2. Performance - Bundle many internal modules into single file (e.g., lodash-es has 600+ modules)

// Works thanks to smart import analysis
import React, { useState } from 'react'

Automatic Discovery

Vite crawls source code to find bare imports and pre-bundles them with Rolldown.

New dependencies discovered after server start trigger re-bundling.

Including Dependencies

Force pre-bundling for dependencies not auto-discovered:

export default defineConfig({
  optimizeDeps: {
    include: [
      'some-package',
      'another-package/nested'  // Deep imports
    ]
  }
})

When to include:

• Dynamically imported (via plugin transform)
• Large dependencies with many internal modules
• CommonJS dependencies

Excluding Dependencies

Skip pre-bundling for small ESM-only dependencies:

export default defineConfig({
  optimizeDeps: {
    exclude: ['small-esm-dep']
  }
})

Monorepo Linked Dependencies

Linked packages are treated as source code by default. If not ESM:

export default defineConfig({
  optimizeDeps: {
    include: ['linked-dep']
  }
})

Restart with --force after making changes to linked deps.

Custom Rolldown Options

export default defineConfig({
  optimizeDeps: {
    rolldownOptions: {
      plugins: [/* Rolldown plugins */],
      // Other Rolldown options
    }
  }
})

Caching

File System Cache

Located in node_modules/.vite. Re-runs when:

• Package lockfile changes (package-lock.json, pnpm-lock.yaml, etc.)
• Patches folder modified
• vite.config.js changes
• NODE_ENV changes

Force re-bundle:

vite --force
# Or delete node_modules/.vite

Browser Cache

Pre-bundled deps are cached with max-age=31536000,immutable.

To debug dependencies with local edits:

1. Disable cache in browser DevTools Network tab
2. Restart Vite with --force
3. Reload page

Entries

Specify custom entry points for discovery:

export default defineConfig({
  optimizeDeps: {
    entries: [
      'src/main.ts',
      'src/other-entry.ts'
    ]
  }
})

By default, all HTML files are used as entries.

esbuildOptions (Deprecated)

Use rolldownOptions instead:

export default defineConfig({
  optimizeDeps: {
    // Deprecated
    esbuildOptions: {},
    // Use instead
    rolldownOptions: {}
  }
})