Worked on the handsontable/handsontable repository to enhance the reliability of the Undo/Redo functionality, focusing on stabilizing editing workflows for enterprise users. Addressed a critical bug that previously caused crashes when changes were nullified, ensuring that all modifications are accurately recorded in the undo stack. Improved the execution order of the beforeChange hook to maintain data integrity during complex editing sequences. Added comprehensive tests to validate the cap of modified values during Undo/Redo operations, preventing regression in future updates. Utilized JavaScript and React, applying front end development and testing skills to deliver robust, maintainable improvements to the codebase.