"Deprecating the Observer Pattern" -- code examples in some other language?

I'm trying to understand the paper Deprecating the Observer Pattern which seems to be somewhat influential in the development of "Reactive" programming.

However, all the examples are in Scala which is hindering my understanding. Has anyone translated these examples into a more commonly known language like Java or JavaScript? Or is there a comparable introduction with examples in a language used by more than like 7 people? :)

If this belongs in a different stackwhatever, please let me know.