Worked on backend stability for the erxes/erxes repository by addressing a bug in product category retrieval. Focused on refining the getChildCategories function in Products.ts, ensuring it consistently returns an empty array when no category IDs are provided or found, rather than an inconsistent object. This adjustment improved the reliability of API contracts and reduced the need for client-side error handling. Utilized TypeScript for backend development and database modeling, aligning data structures to simplify downstream feature implementation. Documented the changes and added inline comments to support future maintainability, contributing to a more robust and predictable backend data flow.