webpack: import + module.exports in the same module caused error

You can use require with export. But not import and module.exports.

This happens if other modules down stream have an unexpected require tree. Babel changes require to import where it isn't supposed to which causes the aforementioned issue @Matthew Herbst. To solve this add "sourceType": "unambiguous" to your babelrc file or babel.config.js so that @babel/plugin-transform-runtime won't do this change of require expression to import in your commonjs files. eg:

module.exports = {
  presets: [
    '@quasar/babel-preset-app'
  ],

  "sourceType": "unambiguous"
}

You can't mix import and module.exports. In the import world, you need to export things.

// Change this
module.exports = foo;

// To this
export default foo;