Persisted store

Problem. Survive page reloads without writing per-store persistence logic.

Solution. Register a Store plugin that subscribes to $subscribe and writes to localStorage. With 1.12.0 you can unregisterPlugin() for test isolation.

import { defineStore, registerPlugin, unregisterPlugin } from '@bquery/bquery/store';

const persist = ({ store }) => {
  const key = `store:${store.id}`;
  const saved = localStorage.getItem(key);
  if (saved) store.$patch(JSON.parse(saved));
  store.$subscribe((state) => localStorage.setItem(key, JSON.stringify(state)));
};

registerPlugin(persist);

export const useSettings = defineStore('settings', {
  state: () => ({ theme: 'light' }),
  actions: {
    setTheme(theme: 'light' | 'dark') { this.theme = theme; },
  },
});

// In tests:
// afterEach(() => unregisterPlugin(persist));

Why it works. $subscribe fires once per action commit, batching multiple mutations into a single storage write.

Related

• Store guide
• Store — Plugin teardown (1.12.0)
• Longer worked example: Examples & Recipes — State management