[carlmungz]

I am currently in the process of doing something similar: https://github.com/CarlMungazi/aprender-js

Once I'm done, I'm probably going to have a proper crack and either building my own tool or collating smaller libraries (and by small I mean they do one thing only and do it very well) into a toolkit I can build stuff very quickly with.

I think the knowledge gained by building your own tool (CSS library, UI framework, state management library etc) seeps into any work you do with other tools or programming in general. It also depends on your aim. You will be more productive using whatever approach you spend time learning deeply.

[omarhaneef]

Boy have I got a treat for you -- or maybe not if you're very knowledgeable in the space -- but this is an amazing course for walking you through the main functions of a framework and the code for some major frameworks:

https://www.udacity.com/course/front-end-frameworks--ud894

I am not associated with Udacity, but I love them so much I promote them every chance I get.

[carlmungz]

Nice - will check it out if I ever get the time.