vite-magic-tree-shaking

Auto-generate tree-shakeable build.lib.entry for Vite from your source directory.

Install

npm install -D vite-magic-tree-shaking
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Usage

// vite.config.ts
import { defineConfig } from 'vite'
import { fileURLToPath } from 'node:url'
import { generateEntries } from 'vite-magic-tree-shaking'

const __dirname = fileURLToPath(new URL('.', import.meta.url))

export default defineConfig({
  build: {
    lib: {
      entry: generateEntries(__dirname),       // scans src/ by default
      // entry: generateEntries(__dirname, 'lib'), // custom source dir
      formats: ['es', 'cjs'],
      fileName: (format, entryName) =>
        `${entryName}.${format === 'es' ? 'js' : 'cjs'}`,
    },
    rollupOptions: {
      external: ['react', 'react-dom'],
      output: {
        preserveModules: true,
        preserveModulesRoot: 'src',
      },
    },
  },
})
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Warn when package.json exports are out of sync

Pass warnOnExportsMismatch: true to get a console.warn at build/dev time if the exports field in package.json does not match the entries resolved from your source directory:

entry: generateEntries(__dirname, 'src', {
  warnOnExportsMismatch: true,
  exports: { formats: ['es', 'cjs'] },
})
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[vite-magic-tree-shaking] package.json exports are out of sync with src entries.
Run: npx vite-magic-tree-shaking generate
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CLI

The package ships a vite-magic binary with two commands.

generate

Reads your source directory, derives the entry map, and safely merges matching entries into the exports field in package.json. Existing custom exports are preserved unless --prune is passed explicitly.

# using npx (no install required)
npx vite-magic-tree-shaking generate

# custom rootDir and srcDir
npx vite-magic-tree-shaking generate /path/to/project lib

# project emits ES modules only
npx vite-magic-tree-shaking generate --formats es

# preview without modifying package.json
npx vite-magic-tree-shaking generate --dry-run
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Example output:

✓ package.json exports updated:
  .
  ./Button/Button
  ./Users
  ./Users/domain/user
  ./Users/types/UserDTO
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validate

Checks that the exports field in package.json matches the entries derived from the source directory. Exits with code 1 if they are out of sync — useful in CI.

npx vite-magic-tree-shaking validate

# also reject custom exports not generated from source
npx vite-magic-tree-shaking validate --strict
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Example output when in sync:

✓ package.json exports are in sync
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Example output from strict validation when out of sync:

✗ package.json exports are out of sync with src entries
  Missing : ./NewFeature
  Extra   : ./OldFeature
  Changed : ./Users

Run: npx vite-magic-tree-shaking generate
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Add to package.json scripts

{
  "scripts": {
    "sync-exports": "vite-magic generate",
    "validate-exports": "vite-magic validate",
    "prebuild": "vite-magic validate"
  }
}
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With prebuild wired up, running npm run build will abort with a clear error if package.json exports are stale, before Vite even starts.

CLI options

Option	Purpose
--formats es,cjs	Match the formats emitted by Vite
--out-dir dist	Set the JavaScript output directory
--types-dir dist	Set the declaration output directory
--no-types	Omit TypeScript declaration conditions
--dry-run	Preview changes without writing
--prune	Explicitly remove exports not generated from source
--strict	Make validate reject additional custom exports

How entries are resolved

Given this structure:

src/
├── index.ts
├── Users/
│   ├── index.ts
│   ├── domain/
│   │   └── user.ts
│   └── types/
│       └── UserDTO.ts
└── Button/
    └── Button.tsx
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generateEntries(__dirname) produces:

{
  index:                 '/abs/src/index.ts',
  Users:                 '/abs/src/Users/index.ts',
  'Users/domain/user':   '/abs/src/Users/domain/user.ts',
  'Users/types/UserDTO': '/abs/src/Users/types/UserDTO.ts',
  'Button/Button':       '/abs/src/Button/Button.tsx',
}
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And vite-magic generate writes the corresponding exports to package.json:

{
  "exports": {
    ".": {
      "types": "./dist/index.d.ts",
      "import": "./dist/index.js",
      "require": "./dist/index.cjs"
    },
    "./Users": {
      "types": "./dist/Users/index.d.ts",
      "import": "./dist/Users.js",
      "require": "./dist/Users.cjs"
    },
    "./Users/domain/user": {
      "types": "./dist/Users/domain/user.d.ts",
      "import": "./dist/Users/domain/user.js",
      "require": "./dist/Users/domain/user.cjs"
    },
    "./Users/types/UserDTO": {
      "types": "./dist/Users/types/UserDTO.d.ts",
      "import": "./dist/Users/types/UserDTO.js",
      "require": "./dist/Users/types/UserDTO.cjs"
    },
    "./Button/Button": {
      "types": "./dist/Button/Button.d.ts",
      "import": "./dist/Button/Button.js",
      "require": "./dist/Button/Button.cjs"
    }
  }
}
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Rules

Source	Entry key
src/index.ts	index
src/Users/index.ts	Users
src/Button/Button.tsx (no index in dir)	Button/Button
src/Users/domain/user.ts (subdir of indexed dir)	Users/domain/user

Directories with an index file use the directory name as key. Their subdirectories are still scanned recursively.

Directories without an index expose each file individually using its relative path (without extension).

Symbolic links are ignored by default. Set followSymlinks: true to follow links whose resolved target remains inside the source directory. Duplicate entry keys and multiple index files fail with a descriptive error instead of silently overwriting an entry.

Ignored files

The following are never included as entries:

• *.test.ts / *.spec.ts
• *.stories.tsx
• *.d.ts / *.d.mts / *.d.cts
• Any file with an extension other than .ts, .tsx, .js, .jsx, .mts, .cts

API

generateEntries(rootDir: string, srcDir?: string, options?: GenerateEntriesOptions): Record<string, string>
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Parameter	Type	Default	Description
rootDir	string	—	Absolute path to the project root
srcDir	string	'src'	Source directory name, relative to rootDir
options	GenerateEntriesOptions	{}	Optional configuration

GenerateEntriesOptions

Option	Type	Default	Description
warnOnExportsMismatch	boolean	false	Emit a console.warn if package.json exports do not match the resolved entries
followSymlinks	boolean	false	Follow links that stay inside srcDir
include	(path: string) => boolean	—	Include matching valid source files
exclude	(path: string) => boolean	—	Exclude matching files or directories
onCollision	'error' | 'overwrite'	'error'	Choose how duplicate keys are handled
exports	ExportsOptions	{}	Output contract used by mismatch warnings

Export-map API

entryRecordToExports(entries, {
  sourceRoot: '/project/src',
  formats: ['es'],
  outDir: 'dist',
  typesOutDir: 'dist',
})
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The generated conditions only include formats that the build emits. Declaration paths retain the source layout, so src/Users/index.ts correctly maps to dist/Users/index.d.ts.

License

MIT