老生常谈Vue中的侦听器watch

const app = Vue.createApp({
        data() {
          return {
            message: "Hello Vue",
            info: { name: "kk", age: 18 },
          };
        },
        methods: {
          changeMessage() {
            this.message = "hello kk";
            this.info = { name: "kk" };
          },
        },

        watch: {
          // 1.默认有两个参数，newValue/oldValue
          message(newValue, oldVale) {
            console.log("message数据发生了变化", newValue, oldValue);
          },
          info(newValue, oldValue) {
            // 2.如果是对象类型，那么拿到的是代理对象
            console.log("info数据发生了变化", newValue, oldValue);
            console.log(newValue.name, oldValue.name);

            // 3.获取原始对象
            console.log({ ...newValue });

<div id="app">
      <h2>{{info.name}}</h2>
      <button @click="changeInfo">修改info</button>
    </div>

 const app = Vue.createApp({
        data() {
          return {
            info: { name: "kk", age: 18 },
          };
        },

        methods: {
          changeInfo() {
            // 创建一个对象，赋值给info
            this.info = { name: "kk" };

            // 直接修改对象里的一个属性
            this.info.name = "kk";
          },
        },

        watch: {
          // 默认watch监听不会进行深度监听
          info(newValue, oldValue) {
            console.log("侦听到info改变", newValue, oldValue);
          },

          // 进行深度监听
          info: {
            handler(newValue, oldValue) {
              console.log("侦听到info改变", newValue, oldValue);
              console.log(newValue === oldValue);
            },

            // 监听器选项
            // info进行深度监听
            deep: true,

            // 第一次渲染直接执行一次监听器
            immediate: true,
          },
        },

        "info.name": function (newValue, oldValue) {
          console.log("name发生改变", newValue, oldValue);
        },
      });

      app.mount("#app");