Ignore Node built-ins in import graph

src/typeScriptImportGraphAnalysis.test.ts

@@ -220,4 +220,48 @@ describe("TypeScript import graph analysis", () => {
     ]);
     expect(graph.hubs.map((hub) => hub.filePath)).toEqual(["src/index.ts", "src/real.ts"]);
   });
+
+  it("classifies Node built-ins as external imports", () => {
+    const projectRoot = makeTempProject("node-builtins");
+    writeTypeScriptProject(projectRoot, {
+      "src/index.ts": [
+        "import fs from 'node:fs';",
+        "import path from 'path';",
+        "export { readFile } from 'node:fs/promises';",
+        "export const modules = [fs, path];",
+        "",
+      ].join("\n"),
+    });
+
+    const graph = analyzeTypeScriptImportGraph({
+      projectRoot,
+      include: ["src/**/*.ts"],
+    });
+
+    expect(graph.status).toBe("ok");
+    expect(graph.summary).toMatchObject({
+      moduleCount: 1,
+      edgeCount: 0,
+      unresolvedImportCount: 0,
+      externalImportCount: 3,
+    });
+    expect(graph.unresolvedImports).toEqual([]);
+    expect(graph.externalImports).toEqual([
+      {
+        from: "src/index.ts",
+        specifier: "node:fs",
+        kind: "import",
+      },
+      {
+        from: "src/index.ts",
+        specifier: "node:fs/promises",
+        kind: "export",
+      },
+      {
+        from: "src/index.ts",
+        specifier: "path",
+        kind: "import",
+      },
+    ]);
+  });
 });

src/typeScriptImportGraphAnalysis.ts

@@ -1,4 +1,4 @@
-import { createRequire } from "node:module";
+import { builtinModules, createRequire } from "node:module";
 import path from "node:path";
 import type { NexusPluginMcpServerCapability } from "dev-nexus";
 import {
@@ -25,6 +25,11 @@ const defaultIncludePatterns = [
   "src/**/*.cts",
 ];
 
+const nodeBuiltinSpecifiers = new Set([
+  ...builtinModules,
+  ...builtinModules.map((moduleName) => `node:${moduleName}`),
+]);
+
 export const typeScriptImportGraphToolDescriptors = [
   {
     name: "typescript.importGraph",
@@ -466,6 +471,14 @@ function buildImportGraph(input: {
         moduleResolutionCache,
       });
       if (!resolved) {
+        if (isNodeBuiltinSpecifier(reference.specifier)) {
+          externalImports.push({
+            from: reference.from,
+            specifier: reference.specifier,
+            kind: reference.kind,
+          });
+          continue;
+        }
         unresolvedImports.push({
           from: reference.from,
           specifier: reference.specifier,
@@ -606,6 +619,10 @@ function resolveImportReference(input: {
   );
 }
 
+function isNodeBuiltinSpecifier(specifier: string): boolean {
+  return nodeBuiltinSpecifiers.has(specifier);
+}
+
 function graphModules(
   filePaths: string[],
   edges: TypeScriptImportGraphEdge[],