App.vue

<template>
  <div id="app">
    <RouteController />
    
    <nav>...</nav>
    
    <router-view/>
  </div>
</template>

RouteController.vue

<script>
export default {
  apollo: {
    user: {
      // ...
    }
  },
  
  async onBeforeEachRoute (to, from, next) {
    await this.$apollo.firstLoad
    if (this.user) {
      
    }
    next()
  }
}
</script>

router.js

export function createRouter (apolloProvider) {
  const router = new Router()
  
  router.beforeEach(async (to, from, next) => {
    const { data: { user } } = await apolloProvider.clients.default.query({
      // ...
    })
    if (user) {
      
    }
    next()
  })
}