父组件，index界面，注意此时expend按钮在父组件中

<template>
  <el-container>
    <el-aside class="Aside">
      <MAside @expendClick="expendClick" :message="message" />
    </el-aside>
    <div class="expend" @click="expend">
      <el-icon class="move" style="margin: 0"><DArrowLeft /></el-icon>
    </div>
    <el-container>
      <el-main style="--el-main-padding: 0">
        <router-view />
      </el-main>
    </el-container>
  </el-container>
</template>

<script>
import MAside from "../components/MAside.vue";
export default {
  name: "Admin",
  components: {
    MAside,
  },
  data() {
    return {
      isCollapse: true,
      message: false,
    };
  },
  created() {
//创建页面之后一段时间自动收缩
    setTimeout(() => {
      this.expend();
    }, 1000);
  },
  methods: {
//展开收缩
    expend() {
      if (this.isCollapse) {
        this.isCollapse = false;
        this.message = false;
        document.querySelector(".Aside").style.width = 0;
        document.querySelector(".Aside").style.opacity = 0;
        document.querySelector(".expend").style.left = "-25px";
        document.querySelector(".expend").style.transform =
          "rotate(180deg) translateY(10%)";
      } else {
        this.isCollapse = true;
        this.message = true;
        this.message = this.isCollapse;
        document.querySelector(".Aside").style.width = "25%";
        document.querySelector(".Aside").style.opacity = 1;
        document.querySelector(".expend").style.left = "25%";
        document.querySelector(".expend").style.transform =
          "rotate(0deg) translateY(-10%)";
      }
    },
//当展开时点击子组件以外地方子组件可调用此父组件的函数，
    expendClick() {
      if (this.isCollapse) {
        this.expend();
      }
    },
  },
};
</script>

子组件，侧边导航栏，用父子间的传参 配合watch来监听侧边栏是否展开，展开则添加点击监听函数，收缩则去除点击监听函数。判断点击是否点击到aside组件外可以通过检查目标元素（e.target）是否不包含在组件的根元素（this.$el）中，如果目标元素在组件之外，我们调用父组件的函数expendClick（）来实现自动收缩，另外因为expend按钮在父组件中，点击按钮也会被判定为false，导致按钮展开功能失效

<template>
  <div class="aside">
    <el-scrollbar style="height: 100%">
      <ul class="item_ul">
        <li
          @click="change"
          class="item_li"
          data-index="0"
          data-routeName="mobileTackOff"
          :class="active == 'mobileTackOff' ? 'active' : ''"
        >
          <el-icon style="margin: 0">
            <Calendar />
          </el-icon>
        </li>
        <li
          @click="change"
          class="item_li"
          data-index="1"
          data-routeName=""
          :class="active == 1 ? 'active' : ''"
        >
          <el-icon style="margin: 0">
            <Stamp />
          </el-icon>
        </li>
      </ul>
    </el-scrollbar>
  </div>
</template>

<script>
export default {
  name: "MAside",
  props: ["message"],
  data() {
    return {
      active: "",
    };
  },
  created() {
    this.active = this.$route.name;
  },
  watch: {
    message(value) {
      console.log(value);
//注意需要先让父组件的expend函数先执行完之后在执行toggleClickEventListener（）来添加监听事件
      setTimeout(() => {
        this.toggleClickEventListener(value);
      }, 100);
    },
  },
  methods: {
    change(e) {
      this.active = e.target.dataset.routeName;
      this.$router.push({ name: e.target.dataset.routeName });
    },
    handleOutsideClick(e) {
      if (!this.$el.contains(e.target)) {
        this.$emit("expendClick");
      }
    },
    toggleClickEventListener(value) {
//判断如果展开了，则添加监听事件
      if (value) {
        document.addEventListener("click", this.handleOutsideClick);
//未展开 则删除监听事件，否则影响父组件收缩展开按钮的正常功能
      } else {
        document.removeEventListener("click", this.handleOutsideClick);
      }
    },
  },
};
</script>

实现效果如下

此时是展开侧边栏，添加了点击监听事件，这时我们点击侧边栏以外部分

 点击这部分

 侧边栏就自动收缩啦