Repos have been able to provide artifacts since forever ago; they just don’t sit in the tree. While you can commit from an action, I’m not sure that’s a great idea.
You're right, artifacts in GitHub repos have been around a long time. I suppose what I was missing was a way to point to a specific built artifact (like a tar.gz from a release) as a dependency, from package.json. As far as I know, it's not possible yet with npm. I can imagine that will be covered somehow with deeper integration of GitHub and the NPM package repository.
Re:NPM Is Joining GitHub
by IsaacSchlueter on Monday March 16, 2020 @06:56PM
(#22599113)
Yes, this has always been possible. Just specify the tarball url instead of a version or range.
With NPM acquired by GitHub, I can imagine them "filling in some steps" by leveraging the fairly new Actions feature, so that repos can provide built artifacts, the same ones as published on NPM. The deeper integration will be an interesting development to watch.