Original great project MitsuhaKitsune/vuex-webextensions, unfortunately it's not working with Manifest v3 and Vue3+Vuex4, so this is completly rewritten version.

Vuex extension sync

A Vuex plugin to sync shared store between background worker script and other extensions contexts: content script, popup, options. Any commit of mutation synced with others automatically and can be persisted in storage.

Current limitations:

• Only mutations synced, not actions (I don't plan to do it because conceptually the action doesn't change the state)
• Only chrome extensions
• Vue3 + Vuex4

Installation

npm i vuex-extension-sync

Usage

Import the plugin into your store file:

import {createStore} from 'vuex';
import VuexExtensionSync from 'vuex-extension-sync';

export default createStore({
  ...
  plugins: [VuexExtensionSync({
    persist: ['somePersistedKey'],
    ignore: ['SOME_MUTATION'],
    debug: false,
  })],
});

Persistent states

⚠ Persistent states using chrome.storage.local to save the state keys in your browser's storage, be sure to grant storage permision.

It's usefull for save settings between browser reload. Use persist: String[] plugin option.

VuexExtensionSync({
  persist: ['somePersistedKey'],
})

Ignored mutations

For skip syncing some mutations use ignore: String[] plugin option.

VuexExtensionSync({
  ignore: ['SOME_MUTATION_1', 'SOME_MUTATION_N'],
})

Debug

For debugging use debug: Boolean|String plugin option. Default info.

Available levels: trace, debug, info, warn, error.

Boolean values mapping: true -> debug, false -> info.

VuexExtensionSync({
  debug: 'warn',
})

Keepalive background worker

Content page keeps reconnecting to terminated worker. When it's reconnects mutation @@SYNC_RECONNECT_MUTATION is fired. If you need to do something on reconnect (resend some state for example), create @@SYNC_RECONNECT_MUTATION mutation with some logic or create it empty and use store.subscribe to catch it.

Strategy

In a real extension, I ran into a problem with state synchronization between all pages.

I have music player control panel extension, when popup play button pressed mutation PLAY sent to content-script and activate play on site.

When site's player starts playing content-script sent back to background mutation PLAY with actual playing state, background updates it's store.

Now if I opened two tabs with same player site, popup's button click sent PLAY to both pages, they started playing and sent back PLAY, background got it from first and replicated to second, second stopped playing and sent it back. So we have a recursion.

To solve this problem I added new broadcast strategy to sync mutations only with master content-script page and ignore other content-script pages, but keep syncing with popup, options pages. Master page is elected by function. When master page is closed there is new election called.

Plugin options: strategy: "broadcast" | "master" - default broadcast. When broadcast chosen it's sync between all pages; When master chosen it's sync only with master content-script which elected by default function "first is master"; electionFunc: function - default null means function "first is master":

function electionFuncFirstIsMaster(ports: Map<Port, Meta>): Port | undefined {
  const [[port] = []] = [...ports.entries()]
    .filter(([, meta]) => meta.usedInMasterStrategy)
    .sort(([, aMeta], [, bMeta]) => aMeta.created - bMeta.created);
  return port;
}

type Port = {
  //@see https://developer.chrome.com/docs/extensions/reference/runtime/#type-Port
}

type Meta = {
    usedInMasterStrategy: boolean, //is used for master port election, cs pages only 
    master: boolean, //is master
    created: number //timestamp
}