Pass variable to html template in nodemailer

What you can do is read the HTML file using fs module in node and then replace the elements that you want changed in the html string using handlebars

var nodemailer = require('nodemailer');var smtpTransport = require('nodemailer-smtp-transport');var handlebars = require('handlebars');var fs = require('fs');var readHTMLFile = function(path, callback) {    fs.readFile(path, {encoding: 'utf-8'}, function (err, html) {        if (err) {            throw err;            callback(err);        }        else {            callback(null, html);        }    });};smtpTransport = nodemailer.createTransport(smtpTransport({    host: mailConfig.host,    secure: mailConfig.secure,    port: mailConfig.port,    auth: {        user: mailConfig.auth.user,        pass: mailConfig.auth.pass    }}));readHTMLFile(__dirname + 'app/public/pages/emailWithPDF.html', function(err, html) {    var template = handlebars.compile(html);    var replacements = {         username: "John Doe"    };    var htmlToSend = template(replacements);    var mailOptions = {        from: 'my@email.com',        to : 'some@email.com',        subject : 'test subject',        html : htmlToSend     };    smtpTransport.sendMail(mailOptions, function (error, response) {        if (error) {            console.log(error);            callback(error);        }    });});

I use it in all my projects. more clean and up to date and understandable. callback hell doesn't exist.sendMail.ts The html file reads with handlebar, puts the relevant variables into the contents, and sends.

import * as nodemailer from 'nodemailer';import * as handlebars from 'handlebars';import * as fs from 'fs';import * as path from 'path';export async function sendEmail(email: string, subject: string, url: string) {  const filePath = path.join(__dirname, '../emails/password-reset.html');  const source = fs.readFileSync(filePath, 'utf-8').toString();  const template = handlebars.compile(source);  const replacements = {    username: "Umut YEREBAKMAZ"  };  const htmlToSend = template(replacements);  const transporter = nodemailer.createTransport({    host: "smtp.mailtrap.io",    port: 2525, // 587    secure: false,    auth: {      user: "fg7f6g7g67",      pass: "asds7ds7d6"    }  });  const mailOptions = {    from: '"noreply@yourdomain.com" <noreply@yourdomain.com>',    to: email,    subject: subject,    text: url,    html: htmlToSend  };  const info = await transporter.sendMail(mailOptions);  console.log("Message sent: %s", info.messageId);  console.log("Preview URL: %s", "https://mailtrap.io/inboxes/test/messages/");}

String replace isn't a good idea because you'll have to restore old strings or create a backup file to be able to change them another time, also it won't be asynchrone and it will cause a problem in every way!you can do it much easier and more cleaner:

just go to your mail options and add context with your variables:

var mailOptions = {  from: 'nginx-iwnl@gmail.com',  to: 'username@gmail.com',  subject: 'Sending email',  template: 'yourTemplate',  context: {                  // <=    username: username,    whatever: variable  }};

next thing to do is openning your html file and call your variables like:

{{username}}