start_server.sh

+npm run build && npm start

webpack.prod.js

+const merge = require("webpack-merge")
+const common = require("./webpack.common.js")
+const BundleAnalyzerPlugin = require("webpack-bundle-analyzer")
+  .BundleAnalyzerPlugin
+
+module.exports = (env) =>
+  merge(common, {
+    mode: "production",
+    plugins: env && env.analyze ? [new BundleAnalyzerPlugin()] : [],
+  })