Worked on the rust-lang/rust repository to enhance file-type detection for auto-run checks, focusing on improving how JavaScript and TypeScript extensions are identified. Consolidated and refactored the detection logic by introducing a generalized language-based matching approach, which increased the accuracy, readability, and maintainability of the codebase. The solution was implemented in Rust and targeted the tidy pipeline, reducing edge-case failures and clarifying function logic. Emphasized code quality improvement and tooling development throughout the process, delivering the feature through two targeted commits. This work contributed to more reliable backend development workflows and streamlined operational efficiency for automated checks.