Mini‑assert is a tiny, cross‑environment assertion library that works in both browsers and Node.js. It provides three levels of checks—`assert` (bug‑level), `assert.expect` (API‑usage errors), and `assert.warning` (non‑critical notices)—each prefixed with a distinct label and handling errors differently (throwing or logging). It’s aimed at developers who need a lightweight, configurable way to surface bugs, misuse, or warnings without pulling in a full‑featured testing framework.