Worked on improving runtime safety and environment detection in the Supabase JavaScript SDKs, focusing on both supabase/supabase-js and supabase/auth-js repositories. Addressed issues where runtime errors could occur in Node-like or non-browser environments by enhancing the isBrowser utility to check for the existence of both window and document objects. This approach ensured more reliable detection of browser contexts, reducing production incidents related to environment misidentification. Utilized TypeScript and JavaScript to deliver these targeted bug fixes, aligning environment checks across libraries and improving the overall developer experience by making cross-library usage safer and more predictable in diverse execution environments.