tsdown

To bundle a TypeScript library into dual ESM and CJS formats, you can configure an automated build process that generates both output formats alongside .d.ts type declarations for npm publishing.

Generating .d.ts declarations is needed when publishing a TypeScript library because it provides accurate type definitions for consumers, ensuring type-safe distribution and correct IDE autocomplete across different module systems.

Validating package.json exports for a dual ESM and CJS package requires checking the export map configuration to ensure correct entry points, output formats, and module resolution for library consumers.

Yes, this bundling approach works for TypeScript libraries with multiple entry points, supporting common build scenarios like single-entry packages and multiple formats while applying export map validation for type-safe distribution.

You can use this to prepare a shared component library for npm publishing by bundling TypeScript source code into dual ESM and CJS outputs with automatic declaration generation and validated export configuration.

Bundling TypeScript libraries into dual formats without export validation risks incorrect package.json integration, broken module resolution, and missing type declarations, which prevents successful type-safe distribution to npm consumers.