Worked on enhancing type safety and event handling for the List event system in the DefinitelyTyped/DefinitelyTyped repository. Focused on expanding the event union by adding the parseComplete event, which addressed a missing event name and improved accuracy for TypeScript users. Updated and extended targeted tests to validate the new event, ensuring that downstream libraries relying on List events benefit from increased reliability and reduced runtime errors. Leveraged TypeScript and type definition skills to deliver these improvements, with a strong emphasis on testing practices. The work contributed to long-term stability and confidence for maintainers and consumers of the List event system.