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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.

like image 747
Gabriel Slomka Avatar asked Dec 15 '17 10:12

Gabriel Slomka


2 Answers

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 
like image 64
Prince Francis Avatar answered Oct 03 '22 23:10

Prince Francis


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.

like image 43
Spain Train Avatar answered Oct 03 '22 22:10

Spain Train