fix(nuxt): clone cookie to detect changes within object (#25007)

packages/nuxt/src/app/composables/cookie.ts

@@ -6,6 +6,7 @@ import { deleteCookie, getCookie, getRequestHeader, setCookie } from 'h3'
 import type { H3Event } from 'h3'
 import destr from 'destr'
 import { isEqual } from 'ohash'
+import { klona } from 'klona'
 import { useNuxtApp } from '../nuxt'
 import { useRequestEvent } from './ssr'
 
@@ -44,7 +45,7 @@ export function useCookie<T = string | null | undefined> (name: string, _opts?:
   }
 
   const hasExpired = delay !== undefined && delay <= 0
-  const cookieValue = hasExpired ? undefined : (cookies[name] as any) ?? opts.default?.()
+  const cookieValue = klona(hasExpired ? undefined : (cookies[name] as any) ?? opts.default?.())
 
   // use a custom ref to expire the cookie on client side otherwise use basic ref
   const cookie = import.meta.client && delay && !hasExpired

test/basic.test.ts

@@ -489,7 +489,19 @@ describe('nuxt composables', () => {
       }
     })
     const cookies = res.headers.get('set-cookie')
-    expect(cookies).toMatchInlineSnapshot('"set-in-plugin=true; Path=/, set=set; Path=/, browser-set=set; Path=/, browser-set-to-null=; Max-Age=0; Path=/, browser-set-to-null-with-default=; Max-Age=0; Path=/"')
+    expect(cookies).toMatchInlineSnapshot('"set-in-plugin=true; Path=/, set=set; Path=/, browser-set=set; Path=/, browser-set-to-null=; Max-Age=0; Path=/, browser-set-to-null-with-default=; Max-Age=0; Path=/, browser-object-default=%7B%22foo%22%3A%22bar%22%7D; Path=/"')
+  })
+  it('updates cookies when they are changed', async () => {
+    const { page } = await renderPage('/cookies')
+    async function extractCookie () {
+      const cookie = await page.evaluate(() => document.cookie)
+      const raw = cookie.match(/browser-object-default=([^;]*)/)![1] ?? 'null'
+      return JSON.parse(decodeURIComponent(raw))
+    }
+    expect(await extractCookie()).toEqual({ foo: 'bar' })
+    await page.getByRole('button').click()
+    expect(await extractCookie()).toEqual({ foo: 'baz' })
+    await page.close()
   })
 })
 

test/fixtures/basic/pages/cookies.vue

@@ -10,10 +10,18 @@ useCookie('browser-accessed-with-default-value', () => 'default')
 useCookie('browser-set').value = 'set'
 useCookie('browser-set-to-null').value = null
 useCookie('browser-set-to-null-with-default', () => 'default').value = null
+
+const objectCookie = useCookie('browser-object-default', {
+  default: () => ({ foo: 'bar' })
+})
 </script>
 
 <template>
   <div>
     <div>cookies testing page</div>
+    <pre>{{ objectCookie }}</pre>
+    <button @click="objectCookie.foo = 'baz'">
+      Change cookie
+    </button>
   </div>
 </template>