fix: don't ignore properties, when put on a default function in CJS context (#2325)

* fix: don't ignore "default" key, when put on a function in CJS context

* test: test case for default.default

packages/vite-node/src/client.ts

@@ -273,7 +273,7 @@ export class ViteNodeRunner {
 
         // returns undefined, when accessing named exports, if default is not an object
         // but is still present inside hasOwnKeys, this is Node behaviour for CJS
-        if (exports.default === null || typeof exports.default !== 'object') {
+        if (isPrimitive(exports.default)) {
           defineExport(exports, p, () => undefined)
           return true
         }

test/cjs/src/default-function.cjs

@@ -0,0 +1,8 @@
+'use strict'
+
+function format() {
+  return ''
+}
+
+module.exports = format
+module.exports.default = format

test/cjs/src/default-function.d.cts

@@ -0,0 +1,3 @@
+declare function format(): string
+
+export default format

test/cjs/test/function-default.test.ts

@@ -0,0 +1,13 @@
+import { describe, expect, it } from 'vitest'
+import format from '../src/default-function.cjs'
+
+describe('correctly puts default on default', () => {
+  it('works on default function', () => {
+    expect(format()).toBe('')
+  })
+
+  it('works on nested default function', () => {
+    // @ts-expect-error types defined only default
+    expect(format.default()).toBe('')
+  })
+})