Exclude node builtins from build

.changeset/odd-ants-appear.md

@@ -0,0 +1,5 @@
+---
+"modular-scripts": major
+---
+
+Exclude node builtins from build

packages/modular-scripts/react-scripts/config/webpack.config.js

@@ -5,6 +5,7 @@ const fs = require('fs');
 const path = require('path');
 const webpack = require('webpack');
 const resolve = require('resolve');
+const builtinModules = require('builtin-modules');
 const PnpWebpackPlugin = require('pnp-webpack-plugin');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
 const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
@@ -632,16 +633,10 @@ module.exports = function (webpackEnv) {
     ].filter(Boolean),
     // Some libraries import Node modules but don't use them in the browser.
     // Tell webpack to provide empty mocks for them so importing them works.
-    node: {
-      module: 'empty',
-      dgram: 'empty',
-      dns: 'mock',
-      fs: 'empty',
-      http2: 'empty',
-      net: 'empty',
-      tls: 'empty',
-      child_process: 'empty',
-    },
+    node: builtinModules.reduce((acc, next) => {
+      acc[next] = false;
+      return acc;
+    }, {}),
     // Turn off performance processing because we utilize
     // our own hints via the FileSizeReporter
     performance: false,

packages/modular-scripts/src/esbuild-scripts/config/createEsbuildConfig.ts

@@ -1,6 +1,7 @@
 import isCi from 'is-ci';
 import * as path from 'path';
 import * as esbuild from 'esbuild';
+import builtinModules from 'builtin-modules';
 import type { Paths } from '../../utils/createPaths';
 import getClientEnvironment from './getClientEnvironment';
 import createEsbuildBrowserslistTarget from '../../utils/createEsbuildBrowserslistTarget';
@@ -34,6 +35,11 @@ export default function createEsbuildConfig(
 
   logger.debug(`Using target: ${target.join(', ')}`);
 
+  // merge and de-duplicate node builtins with external in the parameters
+  const external = [
+    ...new Set((partialConfig.external ?? []).concat(builtinModules)),
+  ];
+
   return {
     entryPoints: [paths.appIndexJs],
     plugins,
@@ -72,5 +78,7 @@ export default function createEsbuildConfig(
     publicPath: paths.publicUrlOrPath,
     nodePaths: (process.env.NODE_PATH || '').split(path.delimiter),
     ...partialConfig,
+    // this was merged previously; do not override.
+    external,
   };
 }