Preset System

/**
 * Core preset paths for essential builder functionality
 * Includes preview-preset for webpack configuration and entry management
 */
const corePresets: string[];

// In .storybook/main.js
module.exports = {
  core: {
    builder: 'webpack4',
  },
  // Core presets are automatically included
};

/**
 * Override preset paths for custom webpack configuration
 * Includes custom-webpack-preset for user configuration integration
 */
const overridePresets: string[];

// Custom webpack configuration is automatically detected and loaded
// through override presets when webpack.config.js exists in config directory

/**
 * Generates webpack configuration for preview iframe
 * @param _ - Unused first parameter (preset convention)
 * @param options - Storybook options with framework and configuration settings
 * @returns Promise resolving to webpack Configuration
 */
function webpack(_: any, options: any): Promise<Configuration>;

/**
 * Generates entry points for preview iframe including HMR client in development
 * @param _ - Unused first parameter (preset convention)
 * @param options - Storybook options with configuration type and settings
 * @returns Promise resolving to array of entry point paths
 */
function entries(_: any, options: any): Promise<string[]>;

// Preview preset is automatically applied through core presets
// It generates comprehensive webpack configuration including:
// - HTML webpack plugin for iframe generation
// - Virtual modules for story and config files
// - Asset loaders and optimization
// - Development server configuration

/**
 * Applies custom webpack configuration with framework integration
 * @param config - Base webpack configuration from Storybook
 * @param options - Storybook options including config directory and webpack config
 * @returns Promise resolving to final webpack configuration
 */
function webpack(config: Configuration, options: Options): Promise<Configuration>;

/**
 * Provides webpack instance for compilation
 * @returns Promise resolving to webpack module
 */
function webpackInstance(): Promise<typeof webpack>;

/**
 * Provides webpack version for compatibility checking
 * @returns Promise resolving to version string
 */
function webpackVersion(): Promise<string>;

// Custom webpack configurations are automatically detected:

// 1. Through webpackConfig option
const storybookOptions = {
  webpackConfig: (config) => {
    config.resolve.alias['@'] = path.resolve(__dirname, 'src');
    return config;
  },
};

// 2. Through webpack.config.js file in config directory
// webpack.config.js
module.exports = ({ config, mode }) => {
  if (mode === 'DEVELOPMENT') {
    config.devtool = 'eval-source-map';
  }
  return config;
};

// 3. Through webpackFinal preset
// .storybook/main.js
module.exports = {
  webpackFinal: (config) => {
    config.module.rules.push({
      test: /\.scss$/,
      use: ['style-loader', 'css-loader', 'sass-loader'],
    });
    return config;
  },
};

// webpack.config.js - Full control mode
module.exports = ({ config, mode }) => {
  // User has full control over configuration
  return customWebpackConfig;
};

// Uses default Webpack4 setup with:
// - Standard loaders and plugins
// - Framework-specific configurations  
// - Storybook-optimized settings

// .storybook/main.js - Preset extension mode
module.exports = {
  webpackFinal: (config) => {
    // Modify existing configuration
    return enhancedConfig;
  },
};