Contributed TypeScript type definitions for the js-untar library to the DefinitelyTyped repository, enhancing type safety and integration for TypeScript projects. The work involved designing a comprehensive typing surface, including a namespace declaration, interfaces for tar file properties, and a strongly typed untar function. Robust type tests were implemented to validate the accuracy and maintainability of the definitions, ensuring reliable compile-time checks for downstream users. By focusing on type definitions and thorough testing, the contribution improved developer experience and reduced integration risks when working with untarring functionality in TypeScript. The project utilized TypeScript and testing methodologies throughout the development process.