How can I add a specific folder from a git repo as a git submodule?

Question

I have a git repo and I want to add a submodule to it. Problem is, the submodule exists as a folder inside another repo. Can I add only that folder as a submodule?

Answer 1

If you really need to include part of an other repository within the history of your own repo, then the subtree merge strategy is more adequate than submodules.

But in both case, the full repository is linked to your repo, not just one directory.
And partial cloning is not possible.

You could try and isolate that directory in its own repository, and then add it as a submodule, but that means its history will be totally seperated from the repo its was coming from originally.