Babel Plugin/Preset files are not allowed to export objects, only functions

I`m tryng to use Babel-loader on an old project, and i notice some issues regarding when babel loader is working on wrapped objects, is this its default behaviour ? I am not sure if this is a bug or something im doing wrong, i could not find much about it over google, so this is my last resource.

Would i need to change something to my code to make it work ?

This are my current specs: Webpack: 3.19.0 babel/core: 7.0.0-beta.34 babel-loader: 8.0.0-beta.0

Please refer to my packages.json if needed:

http://paste.ubuntu.com/26187880/

I`m tryng to load a single file wrapped in a function:

http://paste.ubuntu.com/26187814/

Resuming, something old, that is built like this:

(  window.global = { } )();

This is my webpack config:

const webpackConfig = {
    context: __dirname,
    entry: {
        app: '../../JavaScript/Namespacing.js'
    },
    module: {
        rules: [
          {
            test: /.jsx?$/,
            exclude: /(node_modules|bower_components)/,
            use: {
              loader: 'babel-loader',
            }
          }
        ]
    },
    output: {
      path: __dirname + "/../../static/js",
      filename: "[name].js"
    },
    plugins: [
        new webpack.ProvidePlugin({
            $: "jquery",
            jQuery: "jquery",
            "window.jQuery": "jquery"
        })
    ],
}

And the error i get on my file is the following:

Plugin/Preset files are not allowed to export objects, only functions.

So, am i missing something ?

Thanks for any help.

I got the same error with babel 7.x and and "babel-loader": "^8.0.4"

I solved the issue by changing the following dependencies in package.json. I got the solution from these link

"devDependencies": {
	"@babel/core": "^7.1.6",
	"@babel/preset-env": "^7.1.6",
	"@babel/preset-react": "^7.0.0",
	"babel-loader": "^8.0.4",
	"webpack": "^4.25.1",
	"webpack-cli": "^3.1.2"
}

and in .babelrc

{
	"presets": ["@babel/env", "@babel/react"]
}

or in package.json

"babel": {
	"presets": [
		"@babel/env",
		"@babel/react"
	]
},

If you are using npm then use the following

npm install @babel/core --save-dev
npm install @babel/preset-env --save-dev
npm install @babel/preset-react --save-dev
npm install babel-loader --save-dev
npm install webpack --save-dev
npm install webpack-cli --save-dev

If you are using yarn, then use the following

yarn add @babel/core --dev
yarn add @babel/preset-env --dev
yarn add @babel/preset-react --dev
yarn add babel-loader --dev
yarn add webpack --dev
yarn add webpack-cli --dev

From your package.json, I can see that you are using older plugins and presets meant for Babel v6, which will result in this error message. You need to switch to e.g., @babel/preset-env, then update your .babelrc accordingly (if you provide .babelrc, more specific guidance can be given).

Here is a related ticket with some explanation - https://github.com/babel/babel-loader/issues/540

A few more semi-related notes on what I see in package.json:

The old babel-core dependency is still there. Remove this or update it to version 7.0.0-bridge.0. Similarly, the old react preset is in there, remove it.

If you are using the env preset, you do not need to use the es2015 preset at all. Remove it.

Babel has been moved its packages into its Scope Repository Since version 7.x .

---

the last version of babel packages (in main npmjs ) are :

"babel-core": "^6.26.3",
"babel-preset-env": "^1.7.0",
"babel-preset-react": "^6.24.1",
...

but you have to use The Continued version in @babel/ scoped repository:

by today these are :

"@babel/core": "^7.12.16",
"@babel/preset-env": "^7.12.16",
"@babel/preset-react": "^7.12.13",
...

so you have to uninstall and install them:

npm uninstall babel-core babel-preset-env babel-preset-react
npm install @babel/core @babel/preset-env @babel/preset-react

or :

yarn remove babel-core babel-preset-env babel-preset-react --dev
yarn add @babel/core @babel/preset-env @babel/preset-react --dev

> Note 1: you can add a @ and change first - to / > > Note 2: note that, The babel-loader package is not in babel > package, its a module for webpack to load babel. (it remains > bebel-loader with latest version)

---

after changing babel to its scope you have to make required changes in the .babelrc :

from:

"presets" : ["env","react"]

to :

"presets" : ["@babel/preset-env","@babel/preset-react"]

answers are for old versions. currently this set up is enough:

  "presets": ["@babel/preset-env", "@babel/preset-react"],

if you are using this package "babel-preset-stage-0" on top of those you will still get same error. So uninstall "babel-preset-stage-0" and make sure your all babel packages are starts with "@babel" except "babel-loader". @babel indicates that the package is maintained by the babel team

Most of the packages were not even installed. So, this is the combination which actually worked. Remember to delete your node_modules before testing and changes in .babelrc is important. Updated devDependencies of package.json and .babelrc from.

Updated from:

1. Package.json file:

"devDependencies": {
    "babel-core": "^6.26.3",
    "babel-loader": "^7.1.5",
    "webpack": "^4.41.2",
}


2. .babelrc file:

{
   "presets": [
      "env",
      "react",
      "es2015"
  ],
  "plugins": [
    "transform-class-properties",
    "transform-object-rest-spread",
    "transform-react-jsx"
  ]
}

Updated to:

1. Package.json file:

"devDependencies": {
      "@babel/core": "^7.13.10",
      "@babel/plugin-proposal-class-properties": "^7.8.3",
      "@babel/preset-env": "^7.1.6",
      "@babel/preset-react": "^7.0.0",
      "babel-cli": "^6.26.0",
      "babel-core": "^7.0.0-bridge.0",
      "babel-loader": "^8.0.4",
      "webpack": "^4.46.0"
}


2. .babelrc file:

{
  "presets": ["@babel/preset-env", "@babel/react"],
  "plugins": [
    "transform-class-properties",
    "transform-object-rest-spread",
    "transform-react-jsx"
  ]
}

this worked for me:

npm uninstall --save babel-loader

npm uninstall --save @babel/core

npm install --save-dev babel-loader@^7

and in babelrc:

"presets" : ["env", "react"]