core-js is a modular standard library for JavaScript, providing polyfills for ECMAScript up to the latest versions. It offers comprehensive support for modern JavaScript features, ensuring your code runs consistently across different environments and browsers. core-js includes polyfills for promises, iterators, symbols, typed arrays, and more, allowing developers to utilize cutting-edge functionalities without compromising compatibility. It also enables targeting specific features, optimizing bundle size by including only necessary polyfills.