pinia/references/advanced-hmr.md

---

name: hot-module-replacement description: Enable HMR to preserve store state during development

---

Hot Module Replacement (HMR)

Pinia supports HMR to edit stores without page reload, preserving existing state.

Setup

Add this snippet after each store definition:

import { defineStore, acceptHMRUpdate } from 'pinia'

export const useAuth = defineStore('auth', {
  // store options...
})

if (import.meta.hot) {
  import.meta.hot.accept(acceptHMRUpdate(useAuth, import.meta.hot))
}

Setup Store Example

import { defineStore, acceptHMRUpdate } from 'pinia'

export const useCounterStore = defineStore('counter', () => {
  const count = ref(0)
  const increment = () => count.value++
  return { count, increment }
})

if (import.meta.hot) {
  import.meta.hot.accept(acceptHMRUpdate(useCounterStore, import.meta.hot))
}

Bundler Support

• Vite: Officially supported via import.meta.hot
• Webpack: Uses import.meta.webpackHot
• Any bundler implementing the import.meta.hot spec should work

Nuxt

With @pinia/nuxt, acceptHMRUpdate is auto-imported but you still need to add the HMR snippet manually.

Benefits

• Edit store logic without losing state
• Add/remove state, actions, and getters on the fly
• Faster development iteration