cli，导航完成后获取数据/在导航完成前获取数据

<template>
  <div class="post">
    <div class="loading" v-if="loading">
      Loading...
    </div>

    <div v-if="error" class="error">
      {{ error }}
    </div>

    <div v-if="post" class="content">
      <h2>{{ post.title }}</h2>
      <p>{{ post.body }}</p>
    </div>
  </div>
</template>
export default {
  data () {
    return {
      loading: false,
      post: null,
      error: null
    }
  },
  created () {
    // 组件创建完后获取数据，
    // 此时 data 已经被 observed 了
    this.fetchData()
  },
  watch: {
    // 如果路由有变化，会再次执行该方法
    '$route': 'fetchData'
  },
  methods: {
    fetchData () {
      this.error = this.post = null
      this.loading = true
      // replace getPost with your data fetching util / API wrapper
      getPost(this.$route.params.id, (err, post) => {
        this.loading = false
        if (err) {
          this.error = err.toString()
        } else {
          this.post = post
        }
      })
    }
  }
}

在导航完成前获取数据

export default {
  data () {
    return {
      post: null,
      error: null
    }
  },
  beforeRouteEnter (to, from, next) {
    getPost(to.params.id, (err, post) => 
      if (err) {
        // display some global error message
        next(false)
      } else {
        next(vm => {
          vm.post = post
        })
      }
    })
  },
  // 路由改变前，组件就已经渲染完了
  // 逻辑稍稍不同
  watch: {
    $route () {
      this.post = null
      getPost(this.$route.params.id, (err, post) => {
        if (err) {
          this.error = err.toString()
        } else {
          this.post = post
        }
      })
    }
  }
}