Plugin Configuration

/**
 * Main plugin function that creates a Rollup plugin instance
 * @param options - Plugin configuration options (all optional)
 * @returns Rollup plugin instance with TypeScript support
 */
declare function typescript(options?: RPT2Options): Plugin;

type RPT2Options = Partial<IOptions>;

import typescript from 'rollup-plugin-typescript2';

// Basic usage with default options
export default {
  plugins: [typescript()]
};

// With custom options
export default {
  plugins: [
    typescript({
      check: true,
      verbosity: 2,
      clean: false,
      tsconfig: './src/tsconfig.json',
      tsconfigOverride: {
        compilerOptions: {
          declaration: true
        }
      }
    })
  ]
};

interface IOptions {
  /** Current working directory (defaults to process.cwd()) */
  cwd: string;
  
  /** File patterns to include for compilation */
  include: string | string[];
  
  /** File patterns to exclude from compilation */
  exclude: string | string[];
  
  /** Enable/disable diagnostic checks (transpile-only when false) */
  check: boolean;
  
  /** Logging verbosity level (0=Error, 1=Warning, 2=Info, 3=Debug) */
  verbosity: number;
  
  /** Disable cache and perform clean build */
  clean: boolean;
  
  /** Path to cache directory */
  cacheRoot: string;
  
  /** Bail out on first syntactic or semantic error */
  abortOnError: boolean;
  
  /** Deprecated option for CommonJS compatibility */
  rollupCommonJSResolveHack: boolean;
  
  /** Path to tsconfig.json file */
  tsconfig?: string;
  
  /** Use tsconfig declarationDir instead of Rollup output directory */
  useTsconfigDeclarationDir: boolean;
  
  /** Custom TypeScript module to use instead of peerDependency */
  typescript: typeof tsModule;
  
  /** Override options for tsconfig */
  tsconfigOverride: any;
  
  /** Array of TypeScript transformers (experimental) */
  transformers: TransformerFactoryCreator[];
  
  /** Default options merged with tsconfig */
  tsconfigDefaults: any;
  
  /** Callback function for source map processing */
  sourceMapCallback: (id: string, map: string) => void;
  
  /** Make object-hash ignore unknown types for cache key generation */
  objectHashIgnoreUnknownHack: boolean;
}

const defaultOptions = {
  check: true,
  verbosity: VerbosityLevel.Warning, // 1
  clean: false,
  cacheRoot: "node_modules/.cache/rollup-plugin-typescript2",
  include: ["*.ts+(|x)", "**/*.ts+(|x)", "**/*.cts", "**/*.mts"],
  exclude: ["*.d.ts", "**/*.d.ts", "**/*.d.cts", "**/*.d.mts"],
  abortOnError: true,
  rollupCommonJSResolveHack: false,
  tsconfig: undefined,
  useTsconfigDeclarationDir: false,
  tsconfigOverride: {},
  transformers: [],
  tsconfigDefaults: {},
  objectHashIgnoreUnknownHack: false,
  cwd: process.cwd()
};

// Development build with detailed logging
typescript({
  verbosity: 3,      // Debug level logging
  clean: true,       // Always clean cache
  check: true        // Full type checking
})

// Production build optimized for speed
typescript({
  check: false,      // Skip type checking (transpile only)
  verbosity: 0,      // Only show errors
  clean: false       // Use cache for speed
})

// Custom TypeScript version
typescript({
  typescript: require('ttypescript'), // Alternative TS implementation
  transformers: [myTransformerFactory]
})

/**
 * Configuration precedence (lowest to highest):
 * 1. Plugin defaults
 * 2. tsconfigDefaults
 * 3. tsconfig.json contents
 * 4. tsconfigOverride
 * 5. Forced compiler options
 */
interface ConfigurationFlow {
  /** Base defaults provided by the plugin */
  defaults: Partial<IOptions>;
  
  /** User-provided default values merged first */
  tsconfigDefaults: any;
  
  /** Loaded tsconfig.json configuration */
  tsconfig: any;
  
  /** User overrides applied after tsconfig loading */
  tsconfigOverride: any;
  
  /** Plugin-enforced compiler options (cannot be overridden) */
  forcedOptions: CompilerOptions;
}

// Complex configuration with multiple sources
typescript({
  // Default values merged first
  tsconfigDefaults: {
    compilerOptions: {
      declaration: true,
      sourceMap: true
    }
  },
  
  // Specific tsconfig file
  tsconfig: './build/tsconfig.build.json',
  
  // Override specific options
  tsconfigOverride: {
    compilerOptions: {
      declaration: false,  // Override tsconfig setting
      target: 'ES2020'     // Override tsconfig setting
    }
  }
})