SOURCE

var suggestion=['T恤短袖','夹克长裙','棉衣羽绒服'];
        var app=new Vue({
            el:'#app',
            data:{
                temperature:14,
                suggestion:'夹克长裙'
            },
            methods:{
                add:function(){
                    this.temperature+=5;
                },
                reduce:function(){
                    this.temperature-=5;
                }
            },
            watch:{
                temperature:function(newVal,oldVal){
                    if(newVal>=26){
                        this.suggestion=suggestion[0];
                    }else if(newVal<26 && newVal >=0)
                    {
                        this.suggestion=suggestion[1];
                    }else{
                        this.suggestion=suggestion[2];
                    }
                }
            }

        })

<div id="app">
        <p>今日温度：{{temperature}}°C</p>
        <p>穿衣建议:{{this.suggestion}}</p>
        <p>
            <button @click="add">添加温度</button>
            <button @click="reduce">减少温度</button>

        </p>
</div>