const router = new Router({
  mode: 'history',
  base: process.env.BASE_URL,
  routes: [
    {
      path: "help",
      name: "help",
      meta: {
        title: "新手帮助"
      },
      component: () => import('./views/Help.vue')
    },
    {
      path: "page",
      name: "page",
      meta: {
        title: "宝贝信息"
      },
      component: () => import('./views/Page.vue')
    }
  ]
})

<template>
  <div id="app">
    <header class="header">
      <button @click="back" class="t-xiaoxi iconfont" v-html="icon"></button>
      <h1 class="t-title">{{title}}</h1>
      <router-link to="/search" class="t-sousuo iconfont">&#xe611;</router-link>
    </header>
    <div class="main">
      <router-view></router-view>
    </div>
    <footer class="footer">
　　　　　　// ...
    </footer>
  </div>
</template>

<script>
  export default {
    name: "app",
    data() {
      return {
        title: "我的网站",
        url: '/',
        icon: '&#xe627;'
      }
    },
    methods: {
      back() {
        this.$router.go(this.url);
      },
      update(route) {
        [this.title, this.url, this.icon] = ["我的网站", '/', '&#xe627;'];
        if (!['', '/'].includes(route.path)) { // 判断是否根页面，用于切换标题与返回上一页或回到主页
          [this.title, this.url, this.icon] = [route.meta.title || "", '-1', '&#xe81e;'];
        }
      }
    },
    beforeRouteEnter(to, from, next) {
      next(vm => { //回调函数，此时this指针不可用，可采用回调函数访问。
        vm.update(to);
      })
    },
    beforeRouteUpdate(to, from, next) {
      this.update(to);
      next();
    }
  };
</script>