javascript - 从另一个文件调用函数并在完成后获取结果？

Question

如果第一个函数完成并返回 true，从另一个文件调用函数然后执行其他操作的最佳方法是什么？

module.exports = {
  sendEmail: function(user, subject, text) {
    var smtpTransport = nodemailer.createTransport({
      service: 'gmail',
      auth: {
        user: config.email,
        pass: config.gmlpwd
      }
    });
    var mailOptions = {
      to: user,
      from: config.email,
      subject: subject,
      text: text
    };
    smtpTransport.sendMail(mailOptions, function(err) {
      return true
    });
  }
}

mailer.sendEmail(user.email, subject, text, function(){
     //do something here if the function is done successfully, but it never gets called
});

Answer 1

在 sendMail 函数中，您需要添加该回调作为参数，然后在完成后调用它。

module.exports = {
  sendEmail: function(user, subject, text, cb) {
    var smtpTransport = nodemailer.createTransport({
      service: 'gmail',
      auth: {
        user: config.email,
        pass: config.gmlpwd
      }
    });
    var mailOptions = {
      to: user,
      from: config.email,
      subject: subject,
      text: text
    };
    smtpTransport.sendMail(mailOptions, function(err) {
      return cb(err);
    });
  }
}

mailer.sendEmail(user.email, subject, text, function(){
     // do something here
});

但是，重复执行此操作可能会导致您进入 callback hell ，我建议考虑使用 Promise 或 RxJS 来代替。