It's so depressing that JavaScript is growing in use, especially when I see articles like TFA. I hate that momentum has allowed a clusterf*ck of a language to become the standard for front end and now one of the top 3 for back-end.

Here's Clojure's explanation of transducers: https://clojure.org/reference/transducers

The whole concept is explained more clearly and with far fewer words and code; and the final result is pretty, or at least clean and tidy.