<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>3.天气案例_深度监视</title>
    <script type="text/javascript" src="../vue.js"></script>
</head>
<body>
<div id="root">
    <h3>今天天气很{{showInfo}}</h3>
    <button @click="changeWeather">切换天气</button>
    <hr/>
    <h3>a的值是:{{number.a}}</h3>
    <button @click="number.a++">点我a+1</button>
</div>
<script>
    Vue.config.productionTip = false
    const vm = new Vue({
        el: "#root",
        data: {
            'isHot': true,
            number: {
                a: 1,
                b: 1,
            }
        },
        computed: {
            showInfo() {
                return this.isHot ? '炎热' : '凉爽'
            }

        },
        methods: {
            changeWeather() {
                this.isHot = !this.isHot
            }
        },
        watch: {
            isHot: {
                immediate: true,
                handler(newValue, oldValue) {
                    console.log('isHot 被修改', newValue, oldValue)
                }
            },
            'number': {
                deep: true,  // 深度监视开关
                handler() {
                    console.log('number被改变! ', this.number.a)
                }
            }
        }
    })

</script>
</body>
</html>