[vue]vue中使用$set()方法，解决数据不渲染的问题

<div id="app">
    名称:<input type="text" v-model="linName">
    价格:<input type="text" v-model="price">
    <button @click="save">保存</button>
    查询：<input type="text" v-model="search">
    <ul>
         <li v-for="(item,index) in linshiFun()" :key="index">
                pw_index+1:pw_item.name-pw_item.price <a @click="del(index)">删除</a>
             <a @click="update(index)">修改</a>
         </li>
         <li v-if="linshiFun().length==0">没有数据</li>
    </ul>
</div>
<script src="js/vue.js"></script>
<script type="text/javascript">
    Vue.config.productionTip=false;
    var vm = new Vue({
        el:"#app",
        data: {
            linshi:[
                {"name":"薯片","price":8},
                {"name":"辣条","price":6},
                {"name":"乐百事","price":7},
                {"name":"开心果","price":28},
                {"name":"酸奶","price":8},
                {"name":"牛肉粒","price":17}
            ],
            search:"",
            index:-1,
            linName:"",
            price:""
        }
        ,methods:{
            del:function (index) {
            },
            linshiFun:function () {
              let search = this.search;
                return this.linshi.filter(function(item){
                    return item.name.indexOf(search)>-1;
                })
            },
            update:function (index) {
                this.index = index;
                this.linName = this.linshi[index].name;
                this.price = this.linshi[index].price;
            },
            save:function () {
                this.linshi[this.index].name = this.linName;
                this.linshi[this.index].price = this.price;
            }
        }
    });