Configs from https://www.valentinog.com/blog/webpack-tutorial/

.babelrc

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

package.json

{
  "name": "webpac4-quickstart",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "webpack --mode production",
    "dev": "webpack --mode development",
    "start": "webpack-dev-server --mode development --open",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.1.6",
    "@babel/preset-env": "^7.1.6",
    "@babel/preset-react": "^7.0.0",
    "babel-loader": "^8.0.4",
    "css-loader": "^1.0.1",
    "html-loader": "^0.5.5",
    "html-webpack-plugin": "^3.2.0",
    "mini-css-extract-plugin": "^0.4.4",
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "webpack": "^4.26.0",
    "webpack-cli": "^3.1.2",
    "webpack-dev-server": "^3.1.10"
  }
}

webpack.config.js

const HtmlWebPackPlugin = require('html-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')

module.exports = {
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
        },
      },
      {
        test: /\.html$/,
        use: {
          loader: 'html-loader',
          options: { minimize: true }
        },
      },
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, "css-loader"],
      },
    ],
  },
  plugins: [
    new HtmlWebPackPlugin({
      template: './src/index.html',
      filename: './index.html',
    }),
    new MiniCssExtractPlugin({
      filename: "[name].css",
      chunkFilename: "[id].css",
    }),
  ]
}