fix(types): emit auto-import paths as files, not directories

src/core/build/types.ts

@@ -77,7 +77,10 @@ export async function writeTypes(nitro: Nitro) {
             path = resolvedPath;
           } else {
             const subpath = await lookupNodeModuleSubpath(resolvedPath);
-            path = join(dir, name, subpath || "");
+            path =
+              subpath && subpath !== "./"
+                ? join(dir, name, subpath)
+                : resolvedPath;
           }
         }
       }

test/unit/types-imports.test.ts

@@ -0,0 +1,73 @@
+import { mkdirSync, mkdtempSync, readFileSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "pathe";
+import { describe, expect, it } from "vitest";
+import { createNitro, writeTypes } from "nitropack";
+
+describe("writeTypes auto-import resolution", () => {
+  const fixtureDir = mkdtempSync(join(tmpdir(), "nitro-types-"));
+
+  it("emits a file path (not a package directory) for packages whose exports map only `.`", async () => {
+    const pkgDir = join(fixtureDir, "node_modules", "exports-only-pkg");
+    mkdirSync(join(pkgDir, "dist"), { recursive: true });
+    writeFileSync(
+      join(pkgDir, "package.json"),
+      JSON.stringify({
+        name: "exports-only-pkg",
+        type: "module",
+        exports: {
+          ".": {
+            types: "./dist/index.d.ts",
+            import: "./dist/index.js",
+          },
+        },
+      })
+    );
+    writeFileSync(
+      join(pkgDir, "dist", "index.js"),
+      "export function useExportsOnly() { return true }\n"
+    );
+    writeFileSync(
+      join(pkgDir, "dist", "index.d.ts"),
+      "export declare function useExportsOnly(): boolean\n"
+    );
+
+    mkdirSync(join(fixtureDir, "server"), { recursive: true });
+    writeFileSync(
+      join(fixtureDir, "server", "package.json"),
+      '{ "type": "module" }\n'
+    );
+
+    const nitro = await createNitro({
+      rootDir: fixtureDir,
+      imports: {
+        presets: [
+          {
+            from: "exports-only-pkg",
+            imports: ["useExportsOnly"],
+          },
+        ],
+      },
+    });
+
+    await writeTypes(nitro);
+
+    const generated = readFileSync(
+      join(fixtureDir, ".nitro", "types", "nitro-imports.d.ts"),
+      "utf8"
+    );
+
+    const match = generated.match(
+      /typeof import\('([^']*exports-only-pkg[^']*)'\)/
+    );
+    expect(
+      match,
+      `expected import() referencing exports-only-pkg in:\n${generated}`
+    ).toBeTruthy();
+    const specifier = match![1]!;
+    expect(
+      specifier.endsWith("exports-only-pkg"),
+      `specifier should not end at the package directory, got ${specifier}`
+    ).toBe(false);
+  });
+});