Map‑Or‑Similar is a tiny, dependency‑free polyfill that supplies a drop‑in replacement for JavaScript’s native Map when the environment (browser or Node.js) lacks it. It implements the core Map API (set, get, has, delete, forEach, size) with a focus on speed, letting developers use complex objects as keys without worrying about ES6 support. It’s aimed at front‑end and back‑end developers needing a fast, standards‑compatible Map‑like collection in older runtimes.