The package‑json‑validator library provides a collection of TypeScript functions that rigorously check the contents of a `package.json` file against the npm specification (names, versions, scripts, dependencies, engines, etc.) and returns detailed issue reports. It’s intended for Node / JavaScript developers who want programmatic validation—either embedded in build tools (e.g., ESLint plugin) or run as a one‑off CLI—to catch errors, warnings, and best‑practice recommendations in their package manifests.