pinia-plugin-persistedstate does not update cookies and localStorage in Nuxt 3 (Prod, SSR)

[YuliyaMinsk]

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• Check this box if you encountered the issue using Nuxt and the included module.

Describe the bug

I am using pinia-plugin-persistedstate in a Nuxt 3 project to persist state in cookies. In dev mode, everything works fine, but in production (SSR), the cookies do not update, even though the Pinia state changes.

❗ Additionally:
If I change storage: 'localStorage', data does not get stored in localStorage in production, even though console.log shows the updated state.

Expected behavior

After updating the Pinia state:

In DevTools → Application → Storage → Cookies, the cookie value should be updated.
In DevTools → Application → Storage → LocalStorage, the stored data should be updated.

Steps to reproduce

Install pinia-plugin-persistedstate in Nuxt 3 (npm i pinia-plugin-persistedstate).

Configure persist in nuxt.config.ts:

export default defineNuxtConfig({
  modules: ['@pinia/nuxt', 'pinia-plugin-persistedstate/nuxt'],
  piniaPluginPersistedstate: {
    storage: 'cookies', // Or 'localStorage'
    cookieOptions: {
      sameSite: 'lax',
      secure: false,
      path: '/',
      maxAge: 60 * 60 * 24 * 7, // 7 days
    },
  },
});

Create a Pinia store:

import { defineStore } from 'pinia';

export const useMainStore = defineStore('main', {
  state: () => ({
    currentCompany: null,
  }),
  actions: {
    setCurrentCompany(payload) {
      console.log('🔄 Updating currentCompany:', payload);
      this.currentCompany = payload;
    },
  },
  persist: true,
});

Run the app in prod mode:

npm run build && npm run start

Change the state (setCurrentCompany) and check Cookies/LocalStorage.

Actual behavior

In dev mode: Everything works → document.cookie and localStorage update correctly.
In prod mode: console.log confirms state changes, but Cookies and LocalStorage do not update.

What I have tried

✅ Manually updating cookies using useCookie() – works.
✅ Clearing old cookies before updating – does not help.
✅ Forcing $patch() in Pinia – does not help.
✅ Disabling persist in SSR (persist: process.client ? true : false) – does not help.

Versions

nuxt: 3.15.4
@pinia/nuxt: 0.10.1
pinia-plugin-persistedstate: 4.2.0
node.js: 20.15.1

Additional Information

SSR is enabled (ssr: true).
Cookies only update if manually set using useCookie().
No console errors, but cookies and localStorage do not update in production.

Question

🔹 Is this a bug in pinia-plugin-persistedstate, or am I missing something?
🔹 Why does useCookie() work, but persistedstate does not?

Any help would be greatly appreciated!

Reproduction

The issue only occurs after running npm run build && npm run start, making it impossible to reproduce in an online playground like StackBlitz

System Info

System:
    OS: macOS 15.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 313.69 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.15.1 - ~/.nvm/versions/node/v20.15.1/bin/node
    Yarn: 1.22.22 - /opt/homebrew/bin/yarn
    npm: 10.9.0 - ~/.nvm/versions/node/v20.15.1/bin/npm
  Browsers:
    Chrome: 133.0.6943.141
    Safari: 18.1

Used Package Manager

yarn

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