webpack.server.js

const webpack = require('webpack');
const nodeExternals = require('webpack-node-externals');
const path = require('path');

module.exports = {
  entry: './src/server.js',
 /*  output: {
    path: path.resolve(__dirname , 'dist'),
    filename: 'bundle.js',
    publicPath: '/dist'
  }, */
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'build'),
    publicPath: '/build'
},
  target: 'node',
  mode: 'development',
  externals: nodeExternals(),
  resolve: { extensions: ["*", ".js", ".jsx"] },
  plugins: [
    new webpack.DefinePlugin({
      'process.env': {
        NODE_ENV: `'production'`
      }
    })
  ],
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /(node_modules)/,
        loader: "babel-loader",
        options: { presets: ["@babel/env"] }
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"]
      }
    ]
  }
};