npm install nodemailer
//這個模塊不錯，github上星也比較多，還經常有維護，但是坑也比較多

npm install emailjs --save

npm install nodemailer --save

var nodemailer = require('nodemailer');
var transporter = nodemailer.createTransport({
  //https://github.com/andris9/nodemailer-wellknown#supported-services 支持列表
  service: 'qq',
  port: 465, // SMTP 端口
  secureConnection: true, // 使用 SSL
  auth: {
    user: '768065158@qq.com',
    //這里密碼不是qq密碼，是你設置的smtp密碼
    pass: '*****'
  }
});
// NB! No need to recreate the transporter object. You can use
// the same transporter object for all e-mails
// setup e-mail data with unicode symbols
var mailOptions = {
  from: '768065158@qq.com', // 發(fā)件地址
  to: '528779822@qq.com', // 收件列表
  subject: 'Hello sir', // 標題
  //text和html兩者只支持一種
  text: 'Hello world ?', // 標題
  html: '<b>Hello world ?</b>' // html 內容
};
// send mail with defined transport object
transporter.sendMail(mailOptions, function(error, info){
  if(error){
    return console.log(error);
  }
  console.log('Message sent: ' + info.response);
});

npm install nodemailer-smtp-transport --save

var nodemailer = require('nodemailer');
var smtpTransport = require('nodemailer-smtp-transport');
// 開啟一個 SMTP 連接池
var transport = nodemailer.createTransport(smtpTransport({
 host: "smtp.qq.com", // 主機
 secure: true, // 使用 SSL
 secureConnection: true, // 使用 SSL
 port: 465, // SMTP 端口
 auth: {
  user: "gaolu19901228@qq.com", // 賬號
  pass: "******" // 密碼
 }
}));
// 設置郵件內容
var mailOptions = {
 from: "768065158<768065158@qq.com>", // 發(fā)件地址
 to: "528779822@qq.com", // 收件列表
 subject: "Hello world", // 標題
 text:"hello",
 html: "<b>thanks a for visiting!</b> 世界，你好！" // html 內容
}
// 發(fā)送郵件
transport.sendMail(mailOptions, function(error, response) {
 if (error) {
  console.error(error);
 } else {
  console.log(response);
 }
 transport.close(); // 如果沒用，關閉連接池
});

{ [AuthError: Invalid login - 454 Authentication failed, please open smtp flag first!]
 name: 'AuthError',
 data: '454 Authentication failed, please open smtp flag first!',
 stage: 'auth' }

{ [SenderError: Mail from command failed - 501 mail from address must be same as authorization user]
name: 'SenderError',
data: '501 mail from address must be same as authorization user',
stage: 'mail' }

Invalid login - 535 Authentication failed