webpack.common.js

const path = require("path");
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CopyPlugin = require('copy-webpack-plugin');
const HtmlWebpackTagsPlugin = require('html-webpack-tags-plugin');

module.exports = {
  entry: "./src/index.jsx",
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /(node_modules|bower_components)/,
        loader: "babel-loader",
        options: { presets: ["@babel/env"] }
      }
    ]
  },
  resolve: { extensions: [".js", ".jsx"] },
  output: {
    path: path.resolve(__dirname, "dist"),
    publicPath: "/",
    filename: "bundle.js"
  },
  plugins: [
    new CopyPlugin([{from: 'styles/**/*.css', to: 'css', flatten: true}]),
    new HtmlWebpackPlugin({
      template: 'src/index.ejs'
    }),
    new HtmlWebpackTagsPlugin({tags: ['custom.css'], append: true, publicPath: '/css'})
  ],
};