Worked on stability and correctness across the DataDog/dd-trace-js and ueberdosis/tiptap repositories, focusing on backend and collaborative editing workflows. Addressed a TypeError in ritm.js caching by normalizing module identifiers, adding regression tests to ensure reliability for node:-prefixed built-ins. Improved real-time collaboration in TipTap by ensuring onContentError events are triggered for invalid Yjs transactions, keeping ProseMirror state synchronized. Further enhanced TipTap’s collaboration-caret extension by guarding against null or undefined awareness states, preventing crashes during user disconnects. Maintained code hygiene and consistency throughout, demonstrating proficiency in TypeScript, Node.js, and collaborative editing architecture with a strong emphasis on testing.