Accessing Vuex state when defining Vue-Router routes

I ended up moving the store out of main.js and into store/index.js, and importing it into the router.js file:

import store from './store'

//routes

const routes = [
    { path: '/home', name: 'Home', component: Home },
    { path: '/login', name: 'Login', component: Login },
    { path: '/secret', name: 'Secret', component: SecretPage, meta: { requiresLogin: true }
]    

//guard clause
Router.beforeEach((to, from, next) => {
    if (to.matched.some(record => record.meta.requiresLogin) && store.state.user.authenticated == false) {
        store.commit("setGlobalError", "You need to log in before you can perform this action.")
        next("/Login")
    } else {
        next()
    }
})

You may use router.app to access the root Vue instance the router was injected into, then access store regularly via router.app.$store.

const router = new Router({
    routes,
})

router.beforeEach((to, from, next) => {
    // access store via `router.app.$store` here.
    if (router.app.$store.getters('user')) next();
    else next({ name: 'login' });
})

Here is the API Reference.

Vue 3

The router.app is removed in Vue 3, but you can still add it when using the router as explained in the migration guide:

app.use(router)
router.app = app

As suggested here, what you can do is to export your store from the file it is in and import it in the routes.js. It will be something like following:

You have one store.js:

import Vuex from 'vuex'

//init store
const store = new Vuex.Store({
    state: {
        globalError: '',
        user: {
            authenticated: false
        }
     },
     mutations: {
         setGlobalError (state, error) {
             state.globalError = error
         }
     }
})

export default store

Now in routes.js, you can have:

import Vue from 'vue'
import VueRouter from 'vue-router'
import store from ./store.js

Vue.use(VueRouter)

//define routes
const routes = [
    { path: '/home', name: 'Home', component: Home },
    { path: '/login', name: 'Login', component: Login },
    { path: '/secret', name: 'Secret', component: SecretPage, meta: { requiresLogin: true }
]

Router.beforeEach((to, from, next) => {
    if (to.matched.some(record => record.meta.requiresLogin) && ???) {
        // You can use store variable here to access globalError or commit mutation 
        next("/Login")
    } else {
        next()
    }
})

In main.js also you can import store:

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

import store from './store.js'

//init app
const app = new Vue({
    router: Router,
    store,
    template: '<app></app>',
    components: { App }
}).$mount('#app')