Vue中监视属性的简写形式_vue监视的简写形式-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_45268202/article/details/122194821

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script 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>

    </div>

    <script>
        const vm = new Vue({
            el: "#root",
            data() {
                return {
                    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: {
                //     deep: true,//深度监视
                //     immediate: true,//初始化时让handler调用一下
                //     handler(newValue, oldValue) {

                //         console.log("isHot被修改了");
                //     }
                // },
                // 简写
                // isHot() {
                //     console.log("isHot被修改了");
                // }
            }
        })
        // 正常写法
        // vm.$watch("isHot", {
        //     handler(newValue, oldValue) {
        //         console.log("isHot被修改了");
        //     }
        // })

        // 简写
        vm.$watch("isHot", function (newValue, oldVluea) {
            console.log("isHot被修改了");
        })

    </script>
</body>

</html>