webpack.config.preview.js

const { resolve } = require('path');
const webpack = require('webpack');

const exportDir = resolve(__dirname, 'app/export_files')
module.exports = {
  entry: [
    'react-hot-loader/patch',
    // activate HMR for React

    'webpack-dev-server/client?http://localhost:8080',
    // bundle the client for webpack-dev-server
    // and connect to the provided endpoint

    'webpack/hot/only-dev-server',
    // bundle the client for hot reloading
    // only- means to only hot reload for successful updates

    resolve(exportDir,'src/index.js')
    // the entry point of our app
  ],
  output: {
    filename: 'bundle.js',
    path: resolve(exportDir, 'dist'),
    publicPath: 'http://localhost:8080/'
    // necessary for HMR to know where to load the hot update chunks
  },
  devtool: 'inline-source-map',
  devServer: {
    hot: true,
    contentBase: resolve(exportDir, 'dist'),
    // match the output path
    publicPath: 'http://localhost:8080/',
    // match the output `publicPath`
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        use: [
          'babel-loader',
        ],
        exclude: /node_modules/
      },
      {
        test: /\.css$/,
        use: [
          'style-loader',
          'css-loader?modules',
          'postcss-loader',
        ],
      },
    ],
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin(),
    // enable HMR globally
    new webpack.NamedModulesPlugin(),
    // prints more readable module names in the browser console on HMR updates
  ],
};