The **bit‑vector** library provides a tiny, high‑performance implementation of fixed‑size bit arrays for JavaScript. It lets developers create a bit vector (`createBv`) and efficiently set, clear, or query individual bits (`setBit`, `clearBit`, `getBit`), offering faster and more memory‑efficient alternatives to using plain objects when keys are integer‑like and bounded. It’s aimed at Node.js/ browser developers who need fast, low‑overhead set‑membership or flag storage in performance‑critical code.