> (Functional programming is fine for working with collections. You can do all sort of stuff on collections in a functional way. It’s applied set theory. Beside that I have yet to see some useful application.)

Clearly, you lack real-world FP experience. How are people even able to build entire systems from the ground up using functional languages like Haskell, Elixir, Elm, Clojure, and others.

PS> Not only a JS dev, been doing C# for about a decade.