vue之计算属性computed模板

 <!-- 用户名下拉菜单 -->
          <el-dropdown class="user-name" trigger="click" @command="handleCommand">
            <span class="el-dropdown-link">
              {{username}}
              <i class="el-icon-caret-bottom"></i>
            </span>
            <el-dropdown-menu slot="dropdown">
              <el-dropdown-item divided command="loginout">退出登录</el-dropdown-item>
            </el-dropdown-menu>
          </el-dropdown>

computed: {
    username() {
      let userSO = sessionStorage.getItem("userSO",userSO);
      let username =userSO.userName;
      return username;
     /*  let username = localStorage.getItem("ms_username");
      return username ? username : "admin"; */
    }
  },