Comment that babel-inline-import-loader relies on is not generated

[jimsimon]

I have BABEL_DISABLE_CACHE=1 set and I've tried setting cacheDirectory: false and neither option helps (as expected since the comment is missing from the output).

.babelrc contents:

{
  "presets": [
    [
      "env", {
      "targets": {
        "browsers": [
          "last 2 Chrome versions"
        ]
      },
      "modules": "umd"
    }]
  ],
  "plugins": [
    [
      "babel-plugin-inline-import", {
        "extensions": [
          ".css"
        ]
      }
    ],
    [
      "transform-incremental-dom", {
        "moduleSource": "incremental-dom"
      }
    ],
    ["transform-class-properties"]
  ],
  "env": {
    "test": {
      "plugins": [
        ["istanbul", {
          "exclude": [
            "tests/**/*"
          ]
        }]
      ]
    },
    "production": {
      "presets": ["babili"]
    }
  }
}

webpack.config.js:

const path = require('path')
const HtmlWebpackPlugin = require('html-webpack-plugin')

module.exports = {
  entry: './docs/index.js',
  devtool: 'inline-source-map',
  output: {
    path: __dirname + '/docs/generated',
    filename: 'docs.js'
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: [
          'babel-inline-import-loader',
          'babel-loader'
        ]
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
      filename: 'index.html',
      template: 'docs/template.html'
    })
  ]
}

input code:

import Component from '../../component'
import styles from './styles.css'

customElements.define('wc-button', class WcButton extends Component {
  renderCss () {
    super.renderCss()
    return (
      <style>
        {styles}
      </style>
    )
  }

  render () {
    return <button><slot /></button>
  }
})

relevant output:

  const styles = 'button {\n  background: red;\n}\n';

  customElements.define('wc-button', class WcButton extends _component2.default {
    renderCss() {
      super.renderCss();
      (0, _incrementalDom.elementOpen)('style');

      _renderArbitrary(styles);

      return (0, _incrementalDom.elementClose)('style');
    }

    render() {
      (0, _incrementalDom.elementOpen)('button');
      (0, _incrementalDom.elementVoid)('slot');
      return (0, _incrementalDom.elementClose)('button');
    }
  });

[jimsimon]

After some more research, it seems that setting modules: false instead of modules: "umd" fixes the issue. I tried it with the other possible values for modules and it only seems to work correctly for commonjs and false.