It's a weird choice to write a package manager for a language X in a different language OTHER, because by definition, you've got 100% of the people seriously using the manager able to use the language X , and less than 100% who know this language OTHER, probably significantly less. Even completely ignoring the delightfully-tempting flamebait issues available for this pairing of languages, it seems a mistake to be writing this in anything other than X (Javascript here), because you're needlessly cutting off a large percentage of possible contributors.
Anyways, I suppose my real point and action item is that you might want to drop an answer to my criticism here right in the README.md because it's going to be an issue and you might as well get ahead of it.