script.js

require('dotenv').config()

const nodemailer = require('nodemailer')
const path = require('path')
const fs = require('fs')

// initialize nodemailer
var transporter = nodemailer.createTransport({
  service: 'gmail',
  auth: {
    user: process.env.MAIL_USER,
    pass: process.env.MAIL_PASS,
  },
})

// point to the template folder
const handlebarOptions = {
  viewEngine: {
    partialsDir: path.resolve('./template/'),
    defaultLayout: false,
  },
  viewPath: path.resolve('./template/'),
}

const getMailOptions = (recipientMail, context) => ({
  from: '"ISAG Laboratory" <isag@kmitl.ac.th>', // sender address
  template: 'isag', // the name of the template file, i.e., email.handlebars
  to: recipientMail,
  replyTo: context['อีเมลผู้รับผิดชอบ'],
  subject: `ISAG Warm Welcome 2025 - เชิญชวนเข้าร่วมงาน`,
  context: {
    ...context,
  },
})

const sendMail = async (mailOptions) => {
  const { default: hbs } = await import('nodemailer-express-handlebars')

  // use a template file with nodemailer
  transporter.use('compile', hbs(handlebarOptions))

  try {
    await transporter.sendMail(mailOptions)
  } catch (error) {
    console.log(
      `Nodemailer error sending email to ${mailOptions['ชื่อเล่น']}`,
      error
    )
  }
}

const raw = fs.readFileSync('./mail.csv', 'utf8')

const readCSV = async () => {
  const { default: csv } = await import('neat-csv')

  const data = await csv(raw)
  return data
}

// Send every mail AT ONCE (will get flagged as SPAM)

const sendAllMail = async () => {
  const recipients = await readCSV()
  console.log('========== Script Running... ==========')

  recipients.forEach((recipient) => {
    sendMail(getMailOptions(recipient['อีเมล'], recipient))
    console.log(
      `Sent to: ${recipient['ชื่อ']} ${
        recipient['นามสกุล']
      } at ${new Date().toLocaleTimeString()}`
    )
  })
}

// NOTE: You could try rate limiting to avoid being flagged as spam, but I'm not sure what's the right setting for that.
// Why is this message in spam? Lots of messages from kmitl.ac.th were identified as spam in the past.

// const sendAllMail = async () => {
//   const recipients = await readCSV()
//   console.log('========== Script Running... ==========')

//   for (const recipient of recipients) {
//     await sendMail(getMailOptions(recipient['อีเมล'], recipient))
//     console.log(
//       `Sent to: ${recipient['ชื่อ']} ${
//         recipient['นามสกุล']
//       } at ${new Date().toLocaleTimeString()}`
//     )
//     // rate limit to avoid spam call out
//     await new Promise((resolve) => setTimeout(resolve, 1000)) // 1 email/second
//   }
// }

sendAllMail()