Doesn't work if config is in "babel.config.js" file

• babel-plugin-codegen version: 3.0.0
• nodeversion: 10.13.0
• npm (or yarn) version: 1.12.3

Plugin doesn't work if your Babel config is in babel.config.js, but all works fine if it is in .babelrc

babel.config.js

module.exports = function() {
  return {
    presets: ['babel-preset-expo'],
    plugins: ['codegen'],
  }
}

.babelrc

{
  "presets": ["babel-preset-expo"],
  "plugins": [
    "codegen"
  ]
}

What you did:

// @codegen

module.exports = '
  module.exports = []
'

What happened:

When I use babel.config.js, I get export from module as string "module.exports = []", like there is no top comment "// @codegen".

When I use .babelrc, I get empty array as export from module, as it should be.

Reproduction repository:

https://github.com/serhiipalash/test-babel-codegen

Latest Expo has babel config in babel.config.js, and I don't want to change it as it is the standard for all future releases.