Exported Module Names Issue (Bug?)

1

Hey folks, I’m working on a library which is written in ReScript but intended to be consumed by TS/JS users. My flow is to write in ReScript with @genType annotations, build ReScript → TS/JS, then build TS->JS/Typedefs.

So far this seems to work 99% of the way through, but I’m hitting an issue with the way inline module declarations are named in the resulting files:

// MyFile.res

module Node = {
  @genType
  type t = {
    ...etc
  }

  @genType
  let create = (a, b, c): t => { ... etc }

  @genType
  let isNode = (a: t): bool => { ... etc }
}

@genType
let someOtherFunc (a: Node.t, b: Node.t): () => { ... etc }

With a file like this, abbreviated for clarity, running the rescript build produces .gen.ts files as well as .bs.js files. The .gen.ts files basically provide type-annotated function wrappers which internally just delegate their calls to functions imported from the related .bs.js file.

An example of this copied verbatim from my generated code output is:

import * as ReconcilerBS__Es6Import from './Reconciler.bs';
const ReconcilerBS: any = ReconcilerBS__Es6Import;

export const Node_isNode: <T1>(a:{ readonly symbol: T1 }) => boolean = ReconcilerBS.Node.isNode;

The problem comes in here. The generated TS file expects a named import Node on which the function isNode lives. The corresponding .bs.js file produces an object called $$Node, not Node:

// Reconciler.bs.js

var $$Node = {
  create: create,
  isNode: isNode
};

export {
  $$Node ,
  ...other stuff
}

So after I’ve compiled ReScript->TS/JS then TS->JS/TypeDefs I get runtime errors here because Node.isNode is not a thing. If I manually edit the generated .bs.js to export { $$Node as Node } then everything works as expected.

Is this a bug? Is there a workaround I can use in the meantime?

Thanks in advance

2

Wow, interesting: I think this is specific to using the module name “Node.” Note the generated output in each of these two playground examples:

https://rescript-lang.org/try?code=FAWw9gJgrgNgpgAgHKUQXgQb2AhAXATwAdE8ENtdc84BnPALgQEsA7PAGhwQF9g+gA

https://rescript-lang.org/try?code=FAWw9gJgrgNgpgAgHKTgIQJ4EEB2YAuAFnAE5ICGIiAvAgN7AIL4YAOi+CtDTT+cAZ3wAuBAEsc+ADSMEAX2AKgA

Edit: Right, it seems to do this when the exported name would conflict with a global name in JavaScript (i.e. Node, Map, etc). That makes sense, perhaps the simple thing to do here is just rename my module

3

This is correct. For reference, here’s a list of all of the names affected by this.

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