Turbopack Loader with NAPI-RS StyleX compiler integration

Turbopack loader for an unofficial
napi-rs
compiler that includes the StyleX SWC code transformation under the hood.

Installation

To install the package, run the following command:

``bash
npm install --save-dev @stylexswc/turbopack-plugin
`

Please install @stylexswc/rs-compiler if you haven't done so already:

`bash
npm install --save-dev @stylexswc/rs-compiler
`

Usage

> [!IMPORTANT] Turbopack Limitation: Turbopack does not support webpack
> plugins
> (see Next.js docs).
> This loader only compiles StyleX code but does not extract CSS.
>
> For CSS extraction, you must use the
> @stylexswc/postcss-plugin in your postcss.config.js:
>
> `javascript
> // postcss.config.js
> module.exports = {
> plugins: {
> '@stylexswc/postcss-plugin': {
> include: [
> 'app/*/.{js,jsx,ts,tsx}',
> 'components/*/.{js,jsx,ts,tsx}',
> ],
> rsOptions: {
> dev: process.env.NODE_ENV === 'development',
> },
> },
> autoprefixer: {},
> },
> };
> `

Modify your next.config.ts to configure the loader for Turbopack:

`ts
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
dev: process.env.NODE_ENV !== 'production',
// ... other StyleX options
},
},
},
},
},
},
};

export default nextConfig;
`

Loader Options

$3

#### rsOptions

- Type: Partial
- Optional
- Description: StyleX compiler options that will be passed to the NAPI-RS
compiler. For standard StyleX options, see the
official StyleX documentation.

> [!NOTE] New Features: The include and exclude options are exclusive to
> this NAPI-RS compiler implementation and are not available in the official
> StyleX Babel plugin.

##### rsOptions.include

- Type: (string | RegExp)[]
- Optional
- Description: RS-compiler Only An array of glob patterns or regular
expressions to include specific files for StyleX transformation. When
specified, only files matching at least one of these patterns will be
transformed. Patterns are matched against paths relative to the current
working directory.

##### rsOptions.exclude

- Type: (string | RegExp)[]
- Optional
- Description: RS-compiler Only An array of glob patterns or regular
expressions to exclude specific files from StyleX transformation. Files
matching any of these patterns will not be transformed, even if they match an
include pattern. Patterns are matched against paths relative to the current
working directory.

#### stylexImports

- Type: Array
- Default: ['stylex', '@stylexjs/stylex']
- Description: Specifies where StyleX will be imported from. Supports both
string paths and import aliases.

#### useCSSLayers

- Type: boolean
- Default: false
- Description: Enables CSS cascade layers support for better style isolation.

#### nextjsMode

- Type: boolean
- Default: false
- Description: Enables Next.js-specific optimizations and compatibility
features.

#### extractCSS

- Type: boolean
- Optional
- Default: true
- Description: Controls whether CSS should be extracted into a separate file

$3

#### transformCss

- Type:
(css: string, filePath: string | undefined) => string | Buffer | Promise
- Optional
- Description: Custom CSS transformation function. Since the loader injects CSS
after all loaders, use this to apply PostCSS or other CSS transformations.

$3

`typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
dev: process.env.NODE_ENV !== 'production',
// Include only specific directories
include: ['app//.{ts,tsx}', 'components//.{ts,tsx}'],
// Exclude test files and stories
exclude: ['/.test.', '/.stories.', '/__tests__/'],
},
stylexImports: ['@stylexjs/stylex'],
},
},
},
},
},
};

export default nextConfig;
`

#### Path Filtering Examples

Include only specific directories:

`typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
include: ['app//.{ts,tsx}', 'components//.{ts,tsx}'],
},
},
},
},
},
},
};

export default nextConfig;
`

Exclude test and build files:

`typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
exclude: ['/.test.', '/.spec.', '/dist/'],
},
},
},
},
},
},
};

export default nextConfig;
`

Using regular expressions:

`typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
include: [/app\/.\.tsx$/, /components\/.\.tsx$/],
exclude: [/\.test\./, /\.stories\./],
},
},
},
},
},
},
};

export default nextConfig;
`

Combined include and exclude (exclude takes precedence):

`typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
experimental: {
turbo: {
rules: {
'*.tsx': {
loaders: ['@stylexswc/turbopack-plugin/loader'],
options: {
rsOptions: {
include: ['app//.{ts,tsx}', 'components//.{ts,tsx}'],
exclude: ['/__tests__/', '/__mocks__/'],
},
},
},
},
},
},
};

export default nextConfig;
`

Documentation

- StyleX Documentation
- NAPI-RS compiler for StyleX

Acknowledgments

This loader was inspired by
stylex-webpack`.