I'd love to see the code for this, probably a lot you can learn about low level JS from something like this.
There is no such thing as low-level JS.
Edit: For those who don't believe that JS can't be low-level, please see Wikipedia's definition of "low-level programming language"[1]:
"a programming language that provides little or no abstraction from a computer's instruction set architecture—commands or functions in the language map closely to processor instructions"
If you know literally anything about JavaScript, how it runs, or how processors run, you'll know that JS is not even in the ballpark of "low-level".
Perhaps the parent comment was referring to "JavaScript without frameworks, third-party libraries, or heavy abstractions," which is still not exactly a complex or mystifying arena.
1. https://en.wikipedia.org/wiki/Low-level_programming_language
And as you correctly note, the ransomware code does not come close to qualifying as "low-level".
Huh.