During April 2026, Justin contributed to the oxc-project/oxc repository, focusing on improving formatting correctness for TypeScript and TSX code. He addressed an edge case in the formatter by implementing a fix that preserves trailing commas in arrow functions with default type parameters, ensuring alignment with Prettier’s established behavior. Working primarily with Rust and TypeScript, Justin removed a conditional related to trailing commas, validating the changes against comprehensive JavaScript and TypeScript conformance suites. This work enhanced code consistency and reduced unnecessary diffs in projects using default type parameters, demonstrating careful attention to detail and a strong understanding of formatter development.