Consider the program

  let m = (=) (fun g -> "") (fun v -> "") in 0

If I compile it to ocaml bytecodes and run it it raises an exception as expected:

$ ocamlc -o issues/eqfun.byte ./issues/eqfun.ml 
File "./issues/eqfun.ml", line 2, characters 6-7:
Warning 26: unused variable m.
$ ./issues/eqfun.byte 
Fatal error: exception Invalid_argument("compare: functional value")
$ 

However with js_of_ocaml the exception disappears:

$ js_of_ocaml -o issues/eqfun.js issues/eqfun.byte 
$ node issues/eqfun.js 
$ 

There is a similar issue with the difference operator, e.g., if I change (=) to (<>) in the above example I observe the same difference in behaviour. However with, e.g., the operator compare js_of_ocaml will produce code that raises an exception.

This is with ocaml version 4.04.0, js_of_ocaml version 2.8.4, and node version 6.10.3.