#@esmx/rspack-react

The Rspack React package provides a set of APIs for creating and configuring React-based Rspack applications, supporting React component development, building, and Server-Side Rendering with React Refresh hot module replacement.

#Installation

Use package manager to install @esmx/rspack-react as a development dependency:

npm install @esmx/rspack-react -D

yarn add @esmx/rspack-react -D

pnpm add @esmx/rspack-react -D

bun add @esmx/rspack-react -D

deno add npm:@esmx/rspack-react -D

#Type Exports

#BuildTarget

type BuildTarget = 'node' | 'client' | 'server'

Build target environment type that defines the target environment for application builds, used to configure specific optimizations and features in the build process:

• node: Build code to run in Node.js environment
• client: Build code to run in browser environment
• server: Build code to run in server environment

#RspackAppConfigContext

interface RspackAppConfigContext {
  esmx: Esmx
  buildTarget: BuildTarget
  config: RspackOptions
  options: RspackAppOptions
}

Rspack application configuration context interface provides context information accessible in configuration hook functions:

• esmx: Esmx framework instance
• buildTarget: Current build target (client/server/node)
• config: Rspack configuration object
• options: Application configuration options

#RspackAppChainContext

interface RspackAppChainContext {
  esmx: Esmx
  buildTarget: BuildTarget
  chain: RspackChain
  options: RspackAppOptions
}

Rspack chain configuration context interface provides context information accessible in chain hook functions:

• esmx: Esmx framework instance
• buildTarget: Current build target (client/server/node)
• chain: rspack-chain configuration object for chained configuration
• options: Application configuration options

#RspackAppOptions

interface RspackAppOptions {
  minimize?: boolean
  config?: (context: RspackAppConfigContext) => void | Promise<void>
  chain?: (context: RspackAppChainContext) => void | Promise<void>
}

Rspack application configuration options interface:

• minimize: Whether to enable code compression, defaults to automatic selection based on environment
• config: Configuration hook function for modifying Rspack compilation configuration
• chain: Chain hook function using rspack-chain for flexible configuration modification

#RspackHtmlAppOptions

interface RspackHtmlAppOptions extends RspackAppOptions {
  css?: 'css' | 'js' | false
  loaders?: Partial<Record<keyof typeof RSPACK_LOADER, string>>
  styleLoader?: Record<string, any>
  cssLoader?: Record<string, any>
  lessLoader?: Record<string, any>
  styleResourcesLoader?: Record<string, any>
  swcLoader?: SwcLoaderOptions
  definePlugin?: Record<string, string | Partial<Record<BuildTarget, string>>>
  target?: TargetSetting
}

Rspack HTML application configuration options interface, extends RspackAppOptions:

• css: CSS output method, optional 'css' (separate file) or 'js' (bundled into JS), defaults to automatic selection based on environment
• loaders: Custom loader configuration for replacing default loader implementations
• styleLoader: style-loader configuration options
• cssLoader: css-loader configuration options
• lessLoader: Less compilation options
• styleResourcesLoader: Global style resources auto-injection configuration
• swcLoader: TypeScript/JavaScript compilation options
• definePlugin: Global constant definitions, supports different values for different build targets
• target: Build target compatibility configuration

#RspackReactAppOptions

interface RspackReactAppOptions extends RspackHtmlAppOptions {
  // No additional options, inherits all options from RspackHtmlAppOptions
}

Rspack React application configuration options interface, extends RspackHtmlAppOptions. All options from RspackHtmlAppOptions are available, with React-specific configurations handled automatically by the build tool.

#Function Exports

#createRspackReactApp

function createRspackReactApp(esmx: Esmx, options?: RspackReactAppOptions): Promise<App>

Creates a React Rspack application instance with automatic React configuration, including:

• React JSX/TSX support with automatic runtime
• React Refresh plugin for hot module replacement (development only)
• TypeScript and JavaScript compilation with React transform
• SSR support for React components

Parameters:

• esmx: Esmx framework instance
• options: React application configuration options

Returns:

• Returns a Promise that resolves to the created React application instance

Example:

import type { EsmxOptions } from '@esmx/core';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx, {
        // Custom configuration
        css: 'css',
        chain(context) {
          // Additional chain configuration
          const { chain, buildTarget } = context;
          if (buildTarget === 'client') {
            // Client-specific configuration
          }
        }
      })
    );
  }
} satisfies EsmxOptions;

React-Specific Features:

The createRspackReactApp function automatically configures:

1. JSX/TSX Support: Adds .tsx and .jsx extensions to resolve configuration
2. React Transform: Configures SWC loader with React transform using automatic runtime
3. React Refresh: Automatically enables React Refresh plugin for HMR in client development builds
4. Environment Variables: Sets process.env.NODE_ENV based on build environment

#createRspackHtmlApp

function createRspackHtmlApp(esmx: Esmx, options?: RspackHtmlAppOptions): Promise<App>

Creates an HTML-type Rspack application instance. This function is re-exported from @esmx/rspack and is available for use in React applications if needed.

Parameters:

• esmx: Esmx framework instance
• options: HTML application configuration options

Returns:

• Returns a Promise that resolves to the created HTML application instance

#createRspackApp

function createRspackApp(esmx: Esmx, options?: RspackAppOptions): Promise<App>

Creates a standard Rspack application instance. This function is re-exported from @esmx/rspack and provides the base Rspack functionality.

Parameters:

• esmx: Esmx framework instance
• options: Rspack application configuration options

Returns:

• Returns a Promise that resolves to the created application instance

#Constant Exports

#RSPACK_LOADER

const RSPACK_LOADER: Record<string, string> = {
  builtinSwcLoader: 'builtin:swc-loader',
  lightningcssLoader: 'builtin:lightningcss-loader',
  styleLoader: 'style-loader',
  cssLoader: 'css-loader',
  lessLoader: 'less-loader',
  styleResourcesLoader: 'style-resources-loader',
  workerRspackLoader: 'worker-rspack-loader'
}

Rspack built-in loader identifier mapping object that provides commonly used loader name constants:

• builtinSwcLoader: Rspack built-in SWC loader for processing TypeScript/JavaScript files, configured with React transform for TSX/JSX files
• lightningcssLoader: Rspack built-in lightningcss loader, a high-performance compiler for processing CSS files
• styleLoader: Loader that injects CSS into the DOM
• cssLoader: Loader that parses CSS files and handles CSS modularization
• lessLoader: Loader that compiles Less files to CSS
• styleResourcesLoader: Loader that automatically imports global style resources (variables, mixins, etc.)
• workerRspackLoader: Loader for processing Web Worker files

Using these constants can reference built-in loaders in configuration, avoiding manual string input:

import { RSPACK_LOADER } from '@esmx/rspack-react';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx, {
        loaders: {
          // Use constants to reference loaders
          styleLoader: RSPACK_LOADER.styleLoader,
          cssLoader: RSPACK_LOADER.cssLoader,
          lightningcssLoader: RSPACK_LOADER.lightningcssLoader
        }
      })
    );
  }
};

Notes:

• These loaders are already built into Rspack, requiring no additional installation
• When customizing loader configuration, these constants can be used to replace default loader implementations
• The builtinSwcLoader is automatically configured with React transform for .tsx and .jsx files
• Some loaders (such as builtinSwcLoader) have specific configuration options; please refer to the corresponding configuration documentation

#Module Exports

#rspack

Re-exports all contents from @rspack/core package, providing complete Rspack core functionality, including plugins, loaders, and utilities.

#React-Specific Configuration

#Automatic React Configuration

When using createRspackReactApp, the following React-specific configurations are automatically applied:

1. File Extensions: .tsx and .jsx are added to resolve extensions
2. React Loader Rule: A dedicated rule for .tsx and .jsx files with:
   • SWC loader with TypeScript parser
   • React transform with automatic runtime
   • React Refresh enabled in development (client builds only)
3. React Refresh Plugin: Automatically added for client development builds
4. Environment Variables: process.env.NODE_ENV is set based on build environment

#Customizing React Configuration

You can customize React-specific behavior using the chain hook:

import type { EsmxOptions } from '@esmx/core';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx, {
        chain(context) {
          const { chain, buildTarget } = context;
          
          // Modify React loader configuration
          chain.module
            .rule('react-tsx')
            .use('swc-loader')
            .tap((options) => {
              return {
                ...options,
                jsc: {
                  ...options.jsc,
                  transform: {
                    ...options.jsc.transform,
                    react: {
                      ...options.jsc.transform.react,
                      // Custom React transform options
                      pragma: 'React.createElement',
                      pragmaFrag: 'React.Fragment'
                    }
                  }
                }
              };
            });
        }
      })
    );
  }
} satisfies EsmxOptions;

#SSR Support

React SSR is fully supported. React components can be rendered directly using react-dom/server without special loader configuration:

import { renderToString } from 'react-dom/server';
import { App } from './App';

export async function render(context) {
  const html = renderToString(<App />);
  context.html = html;
}

#Examples

#Basic React Application

import type { EsmxOptions } from '@esmx/core';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx)
    );
  }
} satisfies EsmxOptions;

#React Application with Custom CSS Configuration

import type { EsmxOptions } from '@esmx/core';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx, {
        css: 'css', // Output CSS to separate files
        cssLoader: {
          modules: {
            localIdentName: '[name]__[local]--[hash:base64:5]'
          }
        }
      })
    );
  }
} satisfies EsmxOptions;

#React Application with TypeScript Configuration

import type { EsmxOptions } from '@esmx/core';

export default {
  async devApp(esmx) {
    return import('@esmx/rspack-react').then((m) =>
      m.createRspackReactApp(esmx, {
        swcLoader: {
          jsc: {
            parser: {
              syntax: 'typescript',
              tsx: true,
              decorators: true
            },
            transform: {
              legacyDecorator: true
            }
          }
        }
      })
    );
  }
} satisfies EsmxOptions;

#Notes

• React Version: Requires React 18.0.0 or higher
• TypeScript Support: Full TypeScript support with TSX files
• Hot Module Replacement: React Refresh is automatically enabled in development for client builds
• SSR: Server-side rendering is fully supported without additional configuration
• Performance: Uses Rspack's high-performance build system with React optimizations
• Module Linking: Built-in support for Esmx module linking capabilities