Worked on the increments/qiita-cli repository to update React component type definitions, focusing on preparing the codebase for a smooth migration to React 19. Addressed the challenge of potential null values in HTMLDivElement references by refining type definitions, ensuring continued type safety and forward compatibility. Utilized JavaScript and TypeScript to implement these changes, leveraging front end development expertise with React. The approach emphasized commit-level traceability, allowing for clear documentation and accountability throughout the migration process. This work laid the groundwork for adopting new React features while minimizing risk, supporting a safer and more maintainable upgrade path for the project.