The one good thing about the packaging system is that each dependency is its own version, so you can easily load different versions of the same package.
I'd have to check again, but I looked for specific versions of a JS file and found it repeated multiple times throughout the forest of node_modules.
If side-by-side is desired, then just suffix the folder with a version name. foo.js-1.1 and foo.js-1.0 can be in the root and reused by every package that needs either.
Maybe it does that and I didn't understand what I was looking at.
It's quite naive about it, so it will copy them over and over again. Supposedly there are tools that make everything in node_modules symlinks to the same files.
It's not exactly an advanced and polished system, but it still has a feature that is hard to get with others.
If side-by-side is desired, then just suffix the folder with a version name. foo.js-1.1 and foo.js-1.0 can be in the root and reused by every package that needs either.
Maybe it does that and I didn't understand what I was looking at.