构建侧边栏

在element plus挑选一个菜单组件，创建test页面

<el-col :span="12">
    <h5>自定义颜色</h5>
    <el-menu
      :uniqueOpened="true"
      default-active="2"
      class="el-menu-vertical-demo"
      @open="handleOpen"
      @close="handleClose"
      background-color="#545c64"
      text-color="#fff"
      active-text-color="#ffd04b">
      <el-submenu index="1">
        <template #title>
          <i class="el-icon-location"></i>
          <span>导航一</span>
        </template>
        <el-menu-item-group>
          <template #title>分组一</template>
          <el-menu-item index="1-1">选项1</el-menu-item>
          <el-menu-item index="1-2">选项2</el-menu-item>
        </el-menu-item-group>
        <el-menu-item-group title="分组2">
          <el-menu-item index="1-3">选项3</el-menu-item>
        </el-menu-item-group>
        <el-submenu index="1-4">
          <template #title>选项4</template>
          <el-menu-item index="1-4-1">选项1</el-menu-item>
        </el-submenu>
      </el-submenu>
      <el-menu-item index="2">
        <i class="el-icon-menu"></i>
        <template #title>导航二</template>
      </el-menu-item>
      <el-menu-item index="3" disabled>
        <i class="el-icon-document"></i>
        <template #title>导航三</template>
      </el-menu-item>
      <el-menu-item index="4">
        <i class="el-icon-setting"></i>
        <template #title>导航四</template>
      </el-menu-item>
      <el-submenu index="5">
        <template #title>
          <i class="el-icon-location"></i>
          <span>导航一</span>
        </template>
        <el-menu-item-group>
          <template #title>分组一</template>
          <el-menu-item index="5-1">选项1</el-menu-item>
          <el-menu-item index="5-2">选项2</el-menu-item>
        </el-menu-item-group>
        <el-menu-item-group title="分组2">
          <el-menu-item index="5-3">选项3</el-menu-item>
        </el-menu-item-group>
      </el-submenu>
    </el-menu>
  </el-col>

为了突出重点改造一下

<el-col :span="12">
    <el-menu
      default-active="1-3"
    >
      <el-submenu index="1">
        <template #title>
          <i class="el-icon-location"></i>
          <span>导航一</span>
        </template>
        <el-menu-item index="1-3">选项3</el-menu-item>
        <el-submenu index="1-4">
          <template #title>选项4</template>
          <el-menu-item index="1-4-1">选项1</el-menu-item>
        </el-submenu>
      </el-submenu>
    </el-menu>
  </el-col>

显示效果

添加需要展示的页面

<template>
	<div style="text-align: center">
  <h1>test2</h1>
</template>

<script>
export default {
  name: "Test2"
}
</script>

<style scoped>

</style>

添加路由

{
    path: "/test",
    name: "Test",
    component: () => import("../views/Test"),
    children: [
      {
        path: "/test2",
        name: "Test2",
        component: () => import("../views/Test2"),
      },
    ],
  },

修改test页面

  <el-col :span="12">
    <el-menu
      default-active="1-3"
      router
    >
      <el-submenu index="1">
        <template #title>
          <i class="el-icon-location"></i>
          <span>导航一</span>
        </template>
        // 修改选项3的index
        <el-menu-item index="/test2">选项3</el-menu-item>
        <el-submenu index="1-4">
          <template #title>选项4</template>
          <el-menu-item index="1-4-1">选项1</el-menu-item>
        </el-submenu>
      </el-submenu>
    </el-menu>
  </el-col>
  // 添加路由
  <div class="main-content">
      <router-view />
  </div>

最终效果