警告：.then() 仅排除函数

Question

在 mean stack / nodejs / mongoose 应用程序中，我有这段代码：

User.findByIdAsync(req.params.id)
    .then(handleEntityNotFound(res))
    .then(saveUpdates(req.body))
    .then(sendEmail())  // this is my addition
    .then(respondWithoutResult(res))
    .catch(handleError(res));

函数 sendMail 如下所示：

function sendEmail(body){
  var mailOptions = {
    from: 'Excited User <admin@blabla.com>',
    to: 'johny@gmail.com',
    subject: 'Hello',
    text: 'body text here'
  };

  var smtpConfig = {
    host: config.mailgun.smtp_host,
    port: 465,
    secure: true, 
    auth: {
        user: config.mailgun.smtp_user,
        pass: config.mailgun.smtp_pass
      }
    };

    
  var transporter = nodemailer.createTransport(smtpConfig);
    transporter.sendMail(mailOptions, function(error, info){
        if(error){
            return console.log(error);
        }
        console.log('Message sent: ' + info.response);

    });
}

当我运行它时，我得到一个错误：警告：.then() 仅排除函数但已传递：[object Undefined]

我应该在 sendEmail 中更改什么才能使其与 .then() 一起使用？

Answer 1

因为sendMail supports promises，可以这么简单：

function sendEmail(body) {
  var mailOptions = {
    from: 'Excited User <admin@blabla.com>',
    to: 'johny@gmail.com',
    subject: 'Hello',
    text: 'body text here'
  };

  var smtpConfig = {
    host: config.mailgun.smtp_host,
    port: 465,
    secure: true,
    auth: {
      user: config.mailgun.smtp_user,
      pass: config.mailgun.smtp_pass
    }
  };

  var transporter = nodemailer.createTransport(smtpConfig);

  // Return the promise here.
  return transporter.sendMail(mailOptions);
}

如果要维护日志记录，请将最后一行替换为：

return transporter.sendMail(mailOptions).then(function(info) {
  console.log('Message sent: ' + info.response);
  return info;
}, function(error) {
  console.log(error);
  throw error;
});

编辑：我刚刚注意到 body 参数，我猜这可能是 saveUpdates(req.body)) 的结果。如果是这样，您还需要稍微调整一下您的承诺链：

User.findByIdAsync(req.params.id)
    .then(handleEntityNotFound(res))
    .then(saveUpdates(req.body))
    .then(sendEmail)
    .then(respondWithoutResult(res))
    .catch(handleError(res));

警告：.then() 仅排除函数

Warning: .then() only excepts functions

node.js

express

nodemailer