Worked on the mozilla/rhino repository to address a critical bug in the JavaScript parser’s TokenStream component, focusing on accurate handling of multibyte Unicode characters. Applied expertise in Java and JavaScript to correct length calculations and ensure proper cursor and tokenEnd updates across string literals, template literals, XML literals, and multiline comments. Enhanced the parser’s reliability by developing comprehensive tests that validated edge cases and regression scenarios involving Unicode input. This work improved the robustness of Unicode processing in Rhino, reducing the risk of subtle tokenization errors and supporting downstream applications that rely on precise string manipulation and parser development.