Worked on the TanStack/db repository to enhance the rxdb-db-collection adapter, focusing on improving data integrity and integration stability. Addressed type safety by refactoring type definitions in TypeScript, reducing the risk of runtime errors and streamlining the developer experience. Improved synchronization logic to ensure that only non-deleted documents are included in sync queries, which increased data accuracy across distributed clients. Fixed critical synchronization bugs that previously affected data propagation and reconciliation. Integrated RxJS as a peer dependency to support reactive data flows and compatibility with downstream systems. The work demonstrated strong skills in database management, RxDB, and reactive programming.