1. demonstration.ml

(* Compact *)
List.iter (add_event (fun x -> x.read <- true)) in_fds

(* Less-compact *)
let set_as_read x = x.read <- true in
List.iter (add_event set_as_read) in_fds

(* Least-compact *)
let set_as_read x = x.read <- true in
let add_setread_event_for_single_item item = add_event set_as_read item in
List.iter add_setread_event_for_single_item in_fds

2. comparison.js

import { add_event } from ...

// Least-compact, but in JavaScript
const set_as_read = function(x){ x.read = true }
const add_setread_event_for_single_item = function(item){ add_event(set_as_read, item) }
in_fds.forEach(add_setread_event_for_single_item)