webpack-obfuscator: Uncaught ReferenceError: __webpack_require__ is not defined

My config file:

const webpack = require('webpack');
const JavaScriptObfuscator = require('webpack-obfuscator');
const path = require('path');

const BUILD_DIR = path.resolve(__dirname, './public');
const APP_DIR = path.resolve(__dirname, 'src/');

const config = {
  entry: `${APP_DIR}/index.js`,

  output: {
    path: BUILD_DIR,
    filename: 'bundle.js',
  },
  devServer: {
    historyApiFallback: true,
  },
  module: {
    loaders: [
      {
        enforce: 'pre',
        test: /\.js$/,
        exclude: /node_modules/,
        loader: 'eslint-loader',
      },
      {
        test: /\.js$/,
        include: APP_DIR,
        loader: 'babel-loader',
      },
      {
        test: /\.(png|jpg|gif)$/,
        use: [
          {
            loader: 'file-loader',
            options: {
              name: 'images/[name].[ext]',
            },
          },
        ],
      },
      {
        test: /\.(gif|png|jpe?g|svg)$/i,
        use: [
          'file-loader',
          {
            loader: 'image-webpack-loader',
          },
        ],
      },
    ],
  },
  plugins: [
    new JavaScriptObfuscator({
      rotateUnicodeArray: false,
    }),
  ],
};

module.exports = config;

My package.json:

  "name": "whatever",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "babel-preset-stage-2": "^6.24.1",
    "backendless": "^4.3.0",
    "eslint": "^3.19.0",
    "eslint-config-airbnb": "^14.1.0",
    "eslint-loader": "^1.9.0",
    "eslint-plugin-import": "^2.8.0",
    "eslint-plugin-jsx-a11y": "^4.0.0",
    "eslint-plugin-react": "^6.10.3",
    "react": "^16.0.0",
    "react-bootstrap": "^0.31.5",
    "react-dom": "^16.0.0",
    "react-redux": "^5.0.6",
    "react-router": "^4.2.0",
    "react-router-dom": "^4.2.2",
    "react-scripts": "1.0.14",
    "redux": "^3.7.2",
    "redux-persist": "^5.4.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "watch": "webpack -d --watch",
    "build": "webpack",
    "serve": "serve ./public"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-loader": "^7.1.2",
    "babel-preset-env": "^1.6.1",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "file-loader": "^1.1.6",
    "image-webpack-loader": "^3.4.2",
    "serve": "^6.4.3",
    "webpack": "^3.10.0",
    "webpack-obfuscator": "^0.13.0"
  }
}

I’m not sure why this is happening, any help is appreciated.