Upgrading Bootstrap 3 to Bootstrap 4 with a Shim JS

When I was looking to upgrade a few past projects that I built on Bootstrap v3 to the latest version of Bootstrap, I've found it not as easy as it should be. Upgrading to Font Awesome 5 gave me an idea which I found no results online; I did find that it was previously brought up on GitHub but it was turned down by developers for the lack of time.

So I went online looking if there was a simple solution created by someone else but found none, so I've decided to create my own.

Following a medium article Migration from Bootstrap 3 to Bootstrap 4 by Łukasz Holeczek I've wrote a quick script that would go through the DOM finding previous Bootstrap 3 classes and making changes to match Bootstrap 4 classes.

While it is definitely not perfect, it works pretty well for the few projects I've used it in. There are areas where it is needed to update the classes manually and a few things that could be improved on; such as the input groups prepends/appends.

I am open to suggestions and curious to see what people think of it, if you would make use of something like this? Let me know with the comments below, feel free to use and modify the code any way you wish.

If you are looking to migrate Bootstrap 3 to 4, you can view the project here:
https://github.com/poonasor/bootstrap-v3-shim