`babel-lab` is a lightweight Babel transform that plugs into the **Lab** testing framework, automatically transpiling ES6/JSX files ( `.js`, `.jsx`, `.es`, `.es6` ) on‑the‑fly and inlining source maps so test failures and coverage reports show the original source lines. It’s intended for JavaScript developers who write modern ES6/JSX code and want to run their unit tests with **Lab** without setting up a separate build step.