// Before using this code below, setting your pop mail enable in your gmail account

var transport = nodemailer.createTransport("SMTP", {
        host: "smtp.gmail.com", // hostname
        secureConnection: true, // use SSL
        port: 465, // port for secure SMTP
        auth: {
          user: "your gmail",
          pass: "your password"
        }
      });

transport.sendMail({
        from: "Your name" <your@gmail.com>,
        to: "to1@gmail.com","to2@gmail.com",
        subject: 'Hello', // Subject line
        text: 'Hello world', // plaintext body
      }, function (error, response) {
        if (error) {
          res.send(error)
        } else {
          res.send(response)

        }
      });