For organization and readability, I often wish to break JavaScript files apart into multiple files. However, I also often want these files I extract to be "private" or "internal" to some parent concept.
Something similar to the .NET concept of internal. NPM packages seem to get close, but I worry about ease of use and management using packages in this way just for encapsulation. I'd rather not have to do a version bump every change.
Is there some sort of encapsulation tool that can span multiple files for JavaScript in a Node/Webpack ecosystem?