The **@socketregistry/packageurl-js** library is a zero‑dependency, TypeScript‑first implementation of the [Package URL (purl) specification](https://github.com/package-url/purl-spec). It lets developers parse, build, compare, and manipulate purl strings for more than 40 ecosystems (npm, PyPI, Maven, etc.), with added features such as URL conversion, registry existence checks, immutable updates, and full support for the VERS version‑range companion spec. It’s aimed at JavaScript/TypeScript developers who need a reliable, type‑safe way to identify and work with software package identifiers in tooling, security analysis, or CI pipelines.