侧边菜单

导航栏选中后重新刷新页面会发现选中的导航栏高亮消失了，或者跳到了其它选项，这里的思路就是定义方法，把路由存入到sessionStorage，页面重新加载的时候从sessionStorage中获取

<!--侧边菜单-->
         <el-menu :default-active="active" class="el-menu-vertical-demo" router>

            <router-link to="/user" style="text-decoration: none">
              <el-menu-item index="/user" v-if="isflag" @click="selectMenuItem('/user')"> 
                <el-icon><User /></el-icon>
                <span>User Information</span>
              </el-menu-item>
            </router-link>

            <el-menu-item index="order" v-if="isflag" @click="selectMenuItem('order')">
              <el-icon><Tickets /></el-icon>
              <span>Order Management</span>
            </el-menu-item>

            <el-menu-item index="manage" v-if="userInfo.rolename=='op' ? false : true" @click="selectMenuItem('manage')">
              <el-icon><Reading /></el-icon>
              <span>Task Management</span>
            </el-menu-item>

            <el-menu-item index="task" v-if="isflag" @click="selectMenuItem('task')">
              <el-icon><Calendar /></el-icon>
              <span>Schedule</span>
            </el-menu-item>
          </el-menu>

  data() {
    return {
      active: "/user",
    };
  },

mounted(){
    this.active =  window.sessionStorage.getItem("activerouter");
  },

  methods: {
    selectMenuItem(path) {
      this.active = path
      window.sessionStorage.setItem("activerouter", path);
    },
   }