Almost everyone I've come across who writes JS in a "functional style" has done it because they've had prior experience using a FP language and are applying those lessons to JS. I believe the OP is talking about those FP languages, such as Haskell and Clojure, which have a very different programming experiences.

While JS supports it in many ways, it's still not a style inherent in a multi-paradigm language like Javascript nor is it (really) the primary style in popular frameworks - despite the fact inspiration from FP languages/libraries has been increasingly common in popular frontend frameworks.

Additionally, even if you go full-bore FP on JS, it's still not the same. Almost no one goes full-bore FP in JS because it really doesn't make sense to nor is it an easy thing to do.

(And I say all of this as a frequent user of https://ramdajs.com)