Vue监视属性天气案例``` 今天天气很{{info}} 切换天气 a的值是：{{numbers.a}} 点我让a+1

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8" />
    <title>天气案例_监视属性</title>
    <!-- 引入Vue -->
    <script type="text/javascript" src="../js/vue.js"></script>
</head>

<body>
    <div id="root">
        <h2>今天天气很{{info}}</h2>
        <button @click="changeWeather">切换天气</button>
        <hr>
        <h3>a的值是：{{numbers.a}}</h3>
        <button @click="numbers.a++">点我让a+1</button>
    </div>
</body>

<script type="text/javascript">
    Vue.config.productionTip = false 

    const vm = new Vue({
        el: '#root',
        data: {
            isHot: true,
            numbers:{
                a:1,
                b:1
            }
        },
        computed: {
            info() {
                return this.isHot ? '炎热' : '凉爽'
            }
        },
        methods: {
            changeWeather() {
                this.isHot = !this.isHot
            }
        },
        watch:{
            //正常写法
           /*  isHot:{
                handler(newValue,oldValue){
                    console.log('isHot被修改了',newValue,oldValue)
                }
            }, */
            isHot(newValue,oldValue){
                console.log('asdasdasd')
            }
            
        }
    })
    vm.$watch('isHot',function(newValue,oldValue){
                console.log('asdasdasd')
            })
</script>

</html>