var htmlToText = require('nodemailer-html-to-text').htmlToText;

nodemailerTransport.use('compile', htmlToText(options))

var nodemailer = require('nodemailer');
var htmlToText = require('nodemailer-html-to-text').htmlToText;
var transporter = nodemailer.createTransport();
transporter.use('compile', htmlToText());
transporter.sendMail({
    from: 'me@example.com',
    to: 'receiver@example.com',
    html: '<b>Hello world!</b>'
});