Plenty of languages have immutable data without monads or even being statically typed. Clojure is a fine example. And there is also the somewhat popular https:/

Plenty of languages have immutable data without monads or even being statically typed. Clojure is a fine example. And there is also the somewhat popular https://immutable-js.com/ https://immutable-js.com/ that brings the benefits of immutable data to JavaScript.