Worked on improving cross-environment reliability for the rocicorp/mono repository by addressing runtime errors related to window event listeners in Expo deployments. Focused on frontend development using JavaScript and TypeScript, implementing optional chaining to safely access addEventListener and removeEventListener methods when the window object might be undefined or missing these methods in certain Expo contexts. This approach reduced the risk of crashes and improved stability across both web and React Native environments. The work enhanced event handling robustness, minimized potential support issues, and contributed to more reliable builds, demonstrating a strong understanding of safe global object access patterns in TypeScript.