Context:
Permissive licenses (commonly referred to as "cuck licenses") like the MIT license allow others to modify your software and release it under an unfree license. Copyleft licenses (like the Gnu General Public License) mandate that all derivative works remain free.
Andrew Tanenbaum developed MINIX, a modular operating system kernel. Intel went ahead and used it to build Management Engine, arguably one of the most widespread and invasive pieces of malware in the world, without even as much as telling him. There's nothing Tanenbaum could do, since the MIT license allows this.
Erik Andersen is one of the developers of Busybox, a minimal implementation of that's suited for embedded systems. Many companies tried to steal his code and distribute it with their unfree products, but since it's protected under the GPL, Busybox developers were able to sue them and gain some money in the process.
Interestingly enough, Tanenbaum doesn't seem to mind what intel did. But there are some examples out there of people regretting releasing their work under a permissive license.
The MIT license guarantees that businesses will use it because it's free and they don't have to think about releasing code or hiding their copyright infringement. The developers I've seen using that license, or at least those who put some thought into it, did do because they want companies to use it and therefore boost their credibility through use and bug reports, etc. They knowingly did free work for a bunch of companies as a way to build their CV, basically. Like your very own self-imposed unpaid internship.
The GPL license is also good for developers, as they know they can work on a substantial project and have some protections against others creating closed derived works off of it. It's just a bit more difficult to get enterprise buy-in, which is not a bad thing for many projects.
All my own OSS stuff I always release MIT licensed because I want to be able to use the libraries in my closed source job.
Be really careful with this.
Depending on how you contribute to your OSS code, commits you make on company time are considered property of the company. You could, unknowingly, be forcing your code to be closed source if your company ever decides to make a claim for it.
I prefer to keep things bifurcated. I never reuse my own library and if I do, I rewrite it whole cloth.
“Company time” doesn’t mean much to me, as a remote salaried worker with relatively flexible schedules. Not touching anything but work code from my company machine should be enough, as far as I could understand. Not a lawyer, though.
It will come down to the laws in your country and how much money you plan to spend on lawyers if your employer wants to force the issue.