web app "history" management like git

Maybe my question sound kinda strange and maybe it has been answered somewhere before, but here it is:

i want to have a "git-like" "version/history control system" but for my web app data - that means "cloning", "forking", etc. but for real data - let's say text or images, as well as going back to a specific "commit" and maybe even "merging" different files.

Are there any libraries/implementations for JavaScript like this? I have not specified the data persistence layer.

What i have found is gitlib and nodegit, which enable me this functionality, but for git projects.

Maybe you could point me into the right direction with any other/new/different ideas?

Thanks for your time and dedication.

M.