webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

const DEMO_DIR = path.resolve(__dirname, 'demo');

module.exports = {
  mode: 'development',

  entry: {
    main: path.join(DEMO_DIR, 'main.js')
  },

  output: {
    path: DEMO_DIR,
    filename: '[name].[contenthash].bundle.js'
  },

  devtool: 'eval-source-map',

  devServer: {
    compress: true,
    hot: false,
    host: '0.0.0.0',
    disableHostCheck: true,
    inline: false,
    watchOptions: {
      aggregateTimeout: 1000,
      ignored: 'node_modules',
      poll: false
    },
    stats: {
      all: false,
      modules: true,
      maxModules: 0,
      warnings: true,
      errors: true
    }
  },

  module: {
    rules: [
      {
        test: /\.html$/,
        use: 'polymer-webpack-loader'
      }
    ]
  },

  plugins: [
    new HtmlWebpackPlugin({
      inject: false,
      template: path.join(DEMO_DIR, 'index.ejs')
    })
  ]
};