Is this a bug report?

Yes.

Environment

1. npm ls react-scripts-ts (if you haven’t ejected): 2.16.0
2. node -v: 10.4.1
3. npm -v: 6.1.0
4. yarn --version (if you use Yarn): 1.7.0

Then, specify:

1. Operating system: Windows 10 x64

Steps to Reproduce

Here is the repo with reproduction: https://github.com/FredyC/lingui-typescript-cra

Install with Yarn and yarn start. It's not ejected.

Expected Behavior

Importing JS files should work. I am assuming this is something in this fork since original CRA works with JS files just fine.

Actual Behavior

I am using Lingui project for a localization of the app. The output of that project is compiled JS files. When I try to import these files into the app, it fails with the error.

./src/locale/en/messages.js
Module build failed: Error: Plugin/Preset files are not allowed to export objects, only functions. In D:\workspace\github\lingui-typescript-cra\node_modules\babel-preset-react-app\index.js
    at Array.map (<anonymous>)

That file is indeed exporting object, but there is no reason why it would consider that as a plugin/preset file. The same thing happens when I create a simple JS file like this. It's exporting a function and yet it's wrong.

module.exports = function() {
  console.log(arguments)
}