SOURCE

console 命令行工具 X clear

                    
>
console
new Vue({
  el:"#app",
  data:{
    desc: "Hello world!",
    user: {
      tall: 155
    },
    list: []
  },
  mounted() {
    setTimeout(()=>{
  	  this.user = {
  	  name: "李磊",
  	  age: 18
  	  }; 
      let i= 0
      while(i++<4) {
        this.list.push(i);
      }
    },2000);
    
  },
  watch: {
    user(val) {
      console.log("user change");
    },
    "user.name" (val) {
       console.log("user.name change");
    },
    'user.age' () {
       console.log("user.age change");
    },
    'user.tall' () {
       console.log("user.tall change");
    }
  }
})
<script src="//cdn.bootcss.com/vue/2.3.4/vue.js"></script><div id="app">
<h3 v-text="desc"></h3>
<h4 v-text="user.name"></h4>
<h4 v-text="user.age"></h4>
<input type="text" v-model="user.age"/> 
<h5>{{list.length}}</h5>
<h5 v-if="list.length>1">长度大于1显示</h5>
<h5 v-if="list.length>2">长度大于2显示</h5>
<h5 v-if="list.length>3">长度大于3显示</h5>
</div>