fix(vanilla): respect property enumetrability

src/vanilla.ts

@@ -125,9 +125,13 @@ const buildProxyFunction = (
         return
       }
       const value = Reflect.get(target, key)
+      const { enumerable } = Reflect.getOwnPropertyDescriptor(
+        target,
+        key
+      ) as PropertyDescriptor
       const desc: PropertyDescriptor = {
         value,
-        enumerable: true,
+        enumerable: enumerable as boolean,
         // This is intentional to avoid copying with proxy-compare.
         // It's still non-writable, so it avoids assigning a value.
         configurable: true,

tests/basic.test.tsx

@@ -1,7 +1,7 @@
 import { StrictMode, useEffect, useRef, useState } from 'react'
 import { fireEvent, render, waitFor } from '@testing-library/react'
 import { expect, it, vi } from 'vitest'
-import { proxy, useSnapshot } from 'valtio'
+import { proxy, snapshot, useSnapshot } from 'valtio'
 
 it('simple counter', async () => {
   const obj = proxy({ count: 0 })
@@ -493,3 +493,8 @@ it('sync snapshot between nested components (#460)', async () => {
     getByText('Child: value2')
   })
 })
+
+it('respects property enumerability (#726)', async () => {
+  const x = proxy(Object.defineProperty({ a: 1 }, 'b', { value: 2 }))
+  expect(Object.keys(snapshot(x))).toEqual(Object.keys(x))
+})