fix: merge objects with Module type

src/defu.ts

@@ -10,7 +10,6 @@ function _defu<T>(
   if (!_isPlainObject(defaults)) {
     return _defu(baseObject, {}, namespace, merger);
   }
-
   const object = Object.assign({}, defaults);
 
   for (const key in baseObject) {
@@ -57,8 +56,7 @@ function _isPlainObject(value: unknown): boolean {
     (prototype === null ||
       prototype === Object.prototype ||
       Object.getPrototypeOf(prototype) === null) &&
-    !(Symbol.toStringTag in value) &&
-    !(Symbol.iterator in value)
+    (!(Symbol.toStringTag in value) || !(Symbol.iterator in value))
   );
 }
 

test/defu.test.ts

@@ -1,6 +1,7 @@
 import { expectTypeOf } from "expect-type";
 import { it, describe, expect } from "vitest";
 import { defu, createDefu, defuFn, defuArrayFn } from "../src/defu";
+import * as asteriskImport from "./fixtures/";
 
 // Part of tests brought from jonschlinkert/defaults-deep (MIT)
 const nonObject = [null, undefined, [], false, true, 123];
@@ -50,7 +51,7 @@ describe("defu", () => {
     }>();
   });
 
-  it.skip("should avoid merging objects with custom constructor", () => {
+  it("should avoid merging objects with custom constructor", () => {
     class Test {
       // eslint-disable-next-line no-useless-constructor
       constructor(public value: string) {}
@@ -59,11 +60,12 @@ describe("defu", () => {
     expect(result).toEqual({ test: new Test("a") });
   });
 
-  it.skip("should assign date properly", () => {
+  it("should not merge dates but override", () => {
     const date1 = new Date("2020-01-01");
     const date2 = new Date("2020-01-02");
     const result = defu({ date: date1 }, { date: date2 });
-    expect(result).toEqual({ date: date2 });
+    // Ensure to override, not merge
+    expect(result).toEqual({ date: date1 });
   });
 
   it("should correctly merge different object types", () => {
@@ -232,4 +234,21 @@ describe("defu", () => {
       foo: { bar: { modules: "foo.bar:X,Y" } },
     });
   });
+
+  it("works with asterisk-import", () => {
+    expect(
+      defu(asteriskImport, {
+        a: 2,
+        exp: {
+          anotherNested: 2,
+        },
+      }),
+    ).toStrictEqual({
+      a: 2,
+      exp: {
+        anotherNested: 2,
+        nested: 1,
+      },
+    });
+  });
 });

test/fixtures/index.ts

@@ -0,0 +1 @@
+export { default as exp } from "./nested.js";

test/fixtures/nested.ts

@@ -0,0 +1,3 @@
+export default {
+  nested: 1,
+};