Avoid outputting an empty object for nested module with external bindings

[nojaf]

Hi there,

Could it be possible to not output any JS code when doing external only bindings inside a nested module. Example

type any

type listener

type eventTarget = {}

module EventTarget = {
  @send
  external addEventListener: (eventTarget, string, listener) => unit =
    "addEventListener"
}

leads to

var $$EventTarget = {};

export {
  $$EventTarget ,
}

The existence of $$EventTarget seems unnecessary. Could this be possible?

If so, and this is deemed acceptable I'd be happy to try and contribute this if I get some pointers.

[zth]

I think that makes sense, IIRC I started looking at this at some point... I don't immediately see a problem with not emitting empty modules at all, regardless of whether they're empty because of externals or not. @cristianoc any thoughts?

[cristianoc]

Never emitting an empty module is a bit like never emitting an empty list.

[nojaf]

Never emitting an empty module is a bit like never emitting an empty list.

Not sure if I follow, an empty list could have meaning where an empty module has none after compilation right?

[cknitt]

Already requested this six years ago, this was Bob's response at the time: https://github.com/rescript-lang/rescript/issues/3498#issuecomment-483897516 🙂

I think the problem is that as that module is exported, code in another module could in theory use it (as input to a functor or whatever, although that doesn't make much sense ofc).