Dependencies

Dotenv // To use environment variables
imap // To Read Emails
nodemailer // To Send Emails
html-to-text // To convert html to text when reading emails

Config Object / config.js

SEND_MAIL_CONFIG is configuration for nodemailer

Nodemailer is used to send emails

Nodemailer initialization -

const nodemailer = require('nodemailer');
const transporter = nodemailer.createTransport(SEND_MAIL_CONFIG);

The mail setting can be instantiated in two ways depending on type of using. If the email client is 'gmail' then use the following configuration object -

SEND_MAIL_CONFIG = {
  service: 'gmail',
  auth: {
    user: process.env.EMAIL,
    pass: process.env.PASSWORD,
  },
}

Otherwise use the following configuration

SEND_MAIL_CONFIG: {
    secure: true,
    secureConnection: false, // TLS requires secureConnection to be false
    tls: {
      ciphers: 'SSLv3',
    },
    requireTLS: true,
    port: 465,
    debug: true,
    host: 'smtpout.secureserver.net',
    auth: {
      user: process.env.MAIL_EMAIL,
      pass: process.env.MAIL_PASSWORD,
    },
  },

readMail Config

READ_MAIL_CONFIG = {
  imap: {
    user: process.env.EMAIL, // email address
    password: process.env.PASSWORD, // password
    host: 'imap.gmail.com', // if you are using gmail service
    port: 993, // For gmail service, 465 for others
    authTimeout: 10000, // Stop retrying to read emails
    tls: true,
    tlsOptions: { rejectUnauthorized: false },
  },
};

Applications and Usage

Send Emails / sendEmail.js

To Start sending mails you can use nodemailer native method .sendMail(configObject)

The configObject can contain values like

from - 'user@test.com' // Needs to be a valid email to - ['user1@test.com', 'user2@test.com'] // can be an array of emails or singular email address subject - 'Hello' // Subject of the email text - '' // The actual text content in the body of the email html - '' // Full html of the layout you want to send. More creative work can be done by using this templating and making use of html attribute.

Read Emails / readEmail.js

Step 1 - Create connection with the given credentials

const connection = await imaps.connect(READ_MAIL_CONFIG);

Step 2 - Using the connection object, use another chained method openBox

const box = await connection.openBox('INBOX'); // Can be INBOX, STARRED, SNOOZED

Step 3 - Select the search critera, Will be an array that contains different criteria like UNSEEN, SEEN

const searchCriteria = ['UNSEEN'];

Step 4 - Configure the fetch options that determine what you want to read from the email, This can be header, text, metadata, attachments and so on.

const fetchOptions = {
      bodies: ['HEADER', 'TEXT'],
      markSeen: false,
    };

Step 5 - Run the imap search with the above fetch Options

const results = await connection.search(searchCriteria, fetchOptions);

The variable results will be an array and will contain a lot of values that might be gibbrish for you. The application desired result will be dependent upon you after you have received the results.

Each object in results will contain a special attribut which by which you can extract only a specific part of the whole body.

To receive the text part of the email.

results.forEach((res) => {
  const text = res.parts.filter((part) => {
    return part.which === 'TEXT';
  });
  let emailHTML = text[0].body;

The emailHTML will be in a form of HTML. You need a library to parse your data into text, fot the same reason I am using html-to-text library

Do not forget the last steo to close the connection otherwise the connection will never terminate and a timeout error will be thrown.

connection.end()

Current Application logic / app.js

application on start will run async function bootstrap.

The function will

Send an email to the user defined in the MAIL_SETTINGS
Print Now waiting for 10 seconds
Wait for 10 seconds
Print Fetching the newly send mail
Will read the last mail [ A possibility that if you have not read recent mails, then multiple email would be fetched]
Print the data of the emails

This app is for demonstration purpose only. The actual app can have a totally different approach and absolutely different use case.

Useful Links for references

imap nodemailer html-to-text

samay-codexprt / demo