Worked on the maplibre-gl-js repository to improve Web Worker reliability by developing a build-time ES2020 compatibility test. This feature introduced a process using JavaScript and TypeScript, leveraging build tools to analyze the UMD bundle for ES2022+ class field declarations. The approach involved running esbuild with an ES2020 target and verifying that no downleveling helpers, such as __publicField or _defineProperty, were present, which could otherwise break worker code serialization. By flagging incompatible syntax at build time, this work reduced the risk of runtime failures in worker-enabled scenarios and enhanced the stability of releases across supported environments.