动态的Vue Router标题?

  const routes = [
    {
      path: '/details/:id', component: Details,
      meta: {
        title: "Details"
      }
    }
  ]
  const router = new VueRouter({
    routes
  })
routes设置里面的meta title都是无法改变的,我想要设置标题为`Details: :id`。mounted函数里面的逻辑都是重复的。如何用router.beforeEach实现?