Earlier quoted context omitted.
No, a polyfill is not a library. It's a dozen lines, not a thousand.
> No, a polyfill is not a library Yes, it is. > It's a dozen lines, not a thousand A polyfill can be any size, but there's no size minimum to be a library.
Overly-literal response.
A polyfill is a short snippet to implement a missing feature. Notably almost all recent additions to JS and DOM have been designed to be polyfillable where possible. Generally that means under a thousand lines, by the way.
A library in this context means a set of functionality built on top of the platform, like jQuery, with its own API, etc. "Use a library" and "use a polyfill" are not the same advice.
A polyfill is not a library.