core-js is the more common of the two in our index: it runs on 16,910 websites against 5 for CamanJS, and 2 sites use both. Counts come from real scans, not vendor claims.
CamanJS is a JavaScript library designed for image editing directly on the browser, allowing manipulation of canvas elements.
core-js is a modular standard library for JavaScript, with polyfills for cutting-edge ECMAScript features.
2 sites run both CamanJS and core-js. That is 40% of the sites using CamanJS, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.