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

Hello all, first off just a quick thanks for all the hard work.

I have a small issues, perhaps someone can guide me in the right direction if this isn’t a bug. (which it likely isn’t)

I am trying to build a simple app with Webpack 3.8.1, React 16.1.1, Babel 7.0.0-beta.31 and Babel-loader 8.0.0-beta.0 and I am receiving the following error:

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

.babelrc

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

webpack.conf.js

   ...
  module: {
    noParse: [/.*(pixi\.js).*/],
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules|bower_components)/,
        use: {
          loader: 'babel-loader',
        }
      },
     ...

view.js

import React from 'react';
import ReactDOM from 'react-dom';

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('root')
);

package.json

  "dependencies": {
    "c-p": "^1.3.5",
    "ismobilejs": "^0.4.1",
    "react": "^16.1.1",
    "react-dom": "^16.1.1"
  },
  "devDependencies": {
    "@babel/core": "^7.0.0-beta.31",
    "@babel/preset-env": "^7.0.0-beta.31",
    "babel-loader": "^8.0.0-beta.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-es2017": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "colors": "^1.1.2",
    "css-loader": "^0.28.0",
    "es6-promise-promise": "^1.0.0",
    "eslint": "^3.19.0",
    "extract-text-webpack-plugin": "^3.0.2",
    "file-loader": "^0.11.2",
    "html-webpack-plugin": "^2.28.0",
    "imports-loader": "^0.7.1",
    "jsdoc": "^3.4.3",
    "json-loader": "^0.5.4",
    "less": "^2.7.2",
    "less-loader": "^4.0.3",
    "prompt": "^1.0.0",
    "pug": "^2.0.0-rc.4",
    "pug-loader": "^2.3.0",
    "sqlite3": "^3.1.8",
    "stats.js": "^0.17.0",
    "style-loader": "^0.16.1",
    "webpack": "^3.8.1",
    "webpack-notifier": "^1.5.0",
    "xlsx": "^0.11.8"
  }

Any ideas?

[brenwell]

Awesome, thanks!

npm i @babel/preset-react

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

Did the trick!

[existentialism]

@brenwell you’ll want to make sure your presets are also updated to replace your react preset with @babel/preset-react that matches your @babel/core version (7.0.0-beta.31, in your case).

(Sidenote, since you’re using preset-env, you can drop the es2015/es2017 presets from your package.json!)