Cors‑Helper is a tiny Express middleware library that lets you plug dynamic origin checks into the standard `cors` package. It provides factory functions to build allow‑list or block‑list validators from arrays of IPs, URLs or domain patterns, making CORS configuration easy for Node.js back‑ends that need granular domain whitelisting or blacklisting. It’s aimed at developers building Express APIs who want fine‑grained, programmatic CORS control without writing the matching logic themselves.