<template>
  <el-container>
    <el-aside width="200px">
      <el-menu
          :collapse="isCollapse"
          default-active="1"
          class="el-menu-aside"
      >
        <el-menu-item index="1">
          <el-icon>
            <el-icon-menu/>
          </el-icon>
          <span>菜单 1</span>
        </el-menu-item>
        <el-menu-item index="2">
          <el-icon>
            <el-icon-menu/>
          </el-icon>
          <span>菜单 2</span>
        </el-menu-item>
        <el-menu-item index="3">
          <el-icon>
            <el-icon-menu/>
          </el-icon>
          <span>菜单 3</span>
        </el-menu-item>
      </el-menu>
    </el-aside>
    <el-container>
      <el-header>
        <span @click="toggle">
           <el-icon-expand v-if="isCollapse"></el-icon-expand>
           <el-icon-fold v-else></el-icon-fold>
        </span>
      </el-header>
      <el-main>
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>

<script setup lang="ts">
import {ref} from 'vue'

let isCollapse = ref(false)
let toggle = () => {
  isCollapse.value = !isCollapse.value
}
</script>

<style lang="scss" scoped>

</style>

点击后把整个菜单都隐藏了 菜单的图标都消失了

单纯赋值 效果是对的 很奇怪

let isCollapse = ref(false)
let isCollapse = ref(true)