qc‑core is a lightweight, isomorphic JavaScript utility library that provides core helpers (e.g., noop, null‑returning functions, single‑use guards) and patterns for building class‑based inheritance that works both in Node.js and modern browsers. It’s aimed at developers building the broader “QC ecosystem” who need a small, dependency‑free foundation for safe initialization and read‑only property definitions across server‑ and client‑side code.