删除用户竞赛表单时触发TypeError：无法读取undefined的'schoolName'属性

让我们一步步拆解你遇到的问题，以及对应的修复方案：

核心错误点分析 #

1. 回调函数参数不匹配
   Mongoose的findByIdAndRemove方法回调签名是(err, deletedDocument)——它只会返回错误对象和被删除的文档，并没有第三个user参数。你代码里写的function(err, competition, user)会导致user直接是undefined，自然就没法读取user.schoolName了。

2. 代码执行顺序逻辑错误
   你在res.redirect('/dashboard')之后才定义output，但res.redirect会直接结束HTTP响应，后面的代码根本不会被执行。就算user能正常获取，这部分邮件内容也永远不会被处理。

3. 用户信息获取方式错误
   既然你用了ensureAuthenticated中间件，当前登录用户的信息已经存在req.user对象里了，完全不需要从数据库操作的回调里去拿。

修正后的代码 #

// delete competition form
router.get('/dashboard/users/forms/competition-form/delete/:id', ensureAuthenticated, (req, res, next) => {
  CompetitionForm.findByIdAndRemove(req.params.id, function(err, deletedForm) {
    // 先处理删除失败的情况
    if (err) {
      req.flash('error_msg', 'Failed to delete competition form');
      return res.redirect('/dashboard');
    }

    // 从req.user获取当前登录用户的信息
    const user = req.user;
    // 构建邮件内容
    const output = `
      <h3>Competition Form Deletion</h3>
      <p>Hello ${user.schoolName},</p>
      <p>We are emailing you to make you aware that your competition form has been deleted from our records!</p>
      <br>
      <p>- POL – Puerto Rico</p>
    `;

    // 这里添加你的邮件发送逻辑（比如用nodemailer）
    // 示例参考：
    // transporter.sendMail({
    //   from: 'your-service-email@example.com',
    //   to: user.email,
    //   subject: 'Your Competition Form Has Been Deleted',
    //   html: output
    // }, (mailErr) => {
    //   if (mailErr) {
    //     req.flash('error_msg', 'Form deleted but notification email failed to send');
    //   } else {
    //     req.flash('success_msg', 'Competition form removed successfully!');
    //   }
    //   res.redirect('/dashboard');
    // });

    // 如果暂时不需要邮件发送，保留基础逻辑
    req.flash('success_msg', 'The competition form removed successfully!');
    res.redirect('/dashboard');
  });
});

额外优化建议 #

推荐使用async/await语法替代回调，代码可读性会大幅提升：

router.get('/dashboard/users/forms/competition-form/delete/:id', ensureAuthenticated, async (req, res, next) => {
  try {
    const deletedForm = await CompetitionForm.findByIdAndRemove(req.params.id);
    if (!deletedForm) {
      req.flash('error_msg', 'Competition form not found');
      return res.redirect('/dashboard');
    }

    const user = req.user;
    const output = `
      <h3>Competition Form Deletion</h3>
      <p>Hello ${user.schoolName},</p>
      <p>We are emailing you to make you aware that your competition form has been deleted from our records!</p>
      <br>
      <p>- POL – Puerto Rico</p>
    `;

    // 邮件发送逻辑...

    req.flash('success_msg', 'Competition form removed successfully!');
    res.redirect('/dashboard');
  } catch (err) {
    req.flash('error_msg', 'Failed to delete competition form');
    res.redirect('/dashboard');
  }
});

内容的提问来源于stack exchange，提问作者user8331511