Vim-jslike-oop is a project mainly written in Vim Script, it's free.
VimScript JavaScript Like OOP experiment
This is experiment to explore Vim's capability to support OOP style programming.
It's just experiment.
Currently, I am not intending to be useful for real problem.
Semantics is not consistent in several methods.
There are several attempt to mimic OOP in VimScript.
One of the biggest example is tlib.