Ditto. At my current place my employment agreement doesn't allow me to publicly post code I write in spare time.

My previous employer was a defense contractor, so... yea.

I don't have any side projects that I can share. Sucks, but that's the reality. If I get fired/quit and can't find a job without side projects, I have a list of things in my head to build in ~months if that's what becomes necessary.

You shouldn't put _actual_ work code you wrote on GitHub, but you should write your own small sample programs that demonstrate you know how to use a certain library that you just learned, and then you have it as reference code for yourself later and it shows you know a specific technology.

You should, because it's absolutely grounds for termination at many companies.