Example of using Nodemailer in NodeJS

// @desc    Forgot password
// @route   POST /api/v1/auth/forgotpassword
// @access  Public
// @status  DONE
exports.forgotPassword = asyncHandler(async (req, res, next) => {

  const user = await User.findOne({ email: req.body.email }); // Does the email submitted match with a user in the system?
  if (!user) {
    return next(new ErrorResponse('There is not user with that email', 404)); // Does not exists? Then thrown an error
  }

  // Get userId
  const userId = user.id; // YOU DONT NEED THE USERID. If you decide to delete this, make sure to delete it from the const resetURL also.

  // Get reset token
  const resetToken = user.getResetPasswordToken(); // THIS IS AFUNCTION LOCATED IN YOUR MODEL USING MONGOOSE. SEE BELOW

  // user.password = undefined;
  await user.save({ validateBeforeSave: false });

  // Create reset url
  const resetUrl = `${req.protocol}://${req.get(
    'host'
  )}/auth/resetpassword/${userId}/${resetToken}`;

  const message = `You are receiving this email because you have requested the reset of a password. Please make a PUT request to: \n\n <a href="${resetUrl}">Reset Password</a> `;

  try {
    await sendEmail({ // sendEmail is a function that you can call as many times as you want. SEE BELOW
      email: user.email,
      subject: 'Password reset token',
      message
    });

    res.status(200).json({ success: true, data: 'Email sent', user });
  } catch (err) {
    console.log(err);
    user.resetPasswordToken = undefined;
    user.resetPasswordExpire = undefined;

    await user.save({ validateBeforeSave: false });

    return next(new ErrorResponse('Email could not be sent', 500)); // YOU CAN HANGLE ERRORS HOWEVER YOU WANT. YOU MIGHT DELETE THIS AS IT WILL SHOW YOU AN ERROR(--PROBABLY--).
  }
});

/*
* THIS IS A HELPER FILE CONTAINING A FUNCTION THAT YOU CAN CALL FROM ANY OF YOUR ROUTES.
*/
const nodemailer = require('nodemailer');

const sendEmail = async options => {
  const transporter = nodemailer.createTransport({
    host: process.env.SMTP_HOST, // YOU GET ALL OF THIS FROM E-MAIL SERVER
    port: process.env.SMTP_PORT, // YOU GET ALL OF THIS FROM E-MAIL SERVER
    auth: {
      user: process.env.SMTP_EMAIL, // YOU GET ALL OF THIS FROM E-MAIL SERVER
      pass: process.env.SMTP_PASSWORD // YOU GET ALL OF THIS FROM E-MAIL SERVER
    }
  });

  const message = {
    from: `${process.env.FROM_NAME} <${process.env.FROM_EMAIL}>`,
    to: options.email,
    subject: options.subject,
    text: options.message,
    html: options.message
  };

  const info = await transporter.sendMail(message);

  console.log('Message sent: %s', info.messageId);
};

module.exports = sendEmail;

/*
* FUNCTION TO GET A GENERATE TOKEN LOCATED IN MODEL - you need CRYPTO in order to make it work.
*/
UserSchema.methods.getResetPasswordToken = function() {
  // Generate token
  const resetToken = crypto.randomBytes(20).toString('hex');

  // Hash token and set to resetPasswordToken field
  this.resetPasswordToken = crypto
    .createHash('sha256')
    .update(resetToken)
    .digest('hex');

  // Set expire
  this.resetPasswordExpire = Date.now() + 10 * 60 * 1000;

  return resetToken;
};

/*
* THIS IS THE ROUTE TO USE WITH THE URL SENT IN THE EMAIL.
* AGAIN YOU DON'T NEED USERID -- OPTIONAL
* EXAMPLE OF ROUTE IN FRONT END: /auth/resetpassword/:userid/:resettoken
*/
exports.resetPassword = asyncHandler(async (req, res, next) => {
  // Get hashed token
  const resetPasswordToken = crypto
    .createHash('sha256')
    .update(req.params.resettoken)
    .digest('hex');

  const user = await User.findOne({
    _id: req.params.userid,
    resetPasswordToken,
    resetPasswordExpire: { $gt: Date.now() }
  });

  if (!user) {
    return next(new ErrorResponse('Invalid token', 400));
  }

  // Set new password
  user.password = req.body.password;
  user.resetPasswordToken = undefined;
  user.resetPasswordExpire = undefined;

  await user.save();

  res
    .status(200)
    .json({ success: true, data: 'New password has been created', user });
  // sendTokenResponse(user, 200, res);
});