Mailer

Mailer module is abstraction of node-mailer, and mustache for email template and email subject rendering with variables. However, you can use mailer with plain html, or even replace mustache with another renderer (eg. nunjucks).

Creating and configuring Mailer

To instantiate the Mailer class and prepare it for sending email you need to pass configuration as following:

import { Mailer } from 'node-mariner';

const Mail = new Mailer({
  from: '"Dan Radenkovic" <dan@radenkovic.org>',
  transport: {
    host: 'in-v3.mailjet.com',
    port: 587,  // If TLS on port 587 doesn't work, try using port 465 and/or using SSL instead
    secure: true,
    auth: {
      user: '<YOUR_USERNAME>',
      pass: '<YOUR_PASSWORD>'
    }
  },
  renderer: (content, variables) => content // optional
});

Configuration Object

All keys are mandatory unless stated differently.

key

type

description

from

string

default sender, used in format "name" <email>, can be overridden

transport.host

string

SMTP

transport.port

number

SMTP PORT (eg. 25, 587, 465)

transport.secure

boolean

whether to use encrypted transport

transport.auth

object

SMTP server credentials (auth.user, auth.pass)

renderer (optional)

function

optional function that has two arguments (content, variables) described below

TIP: If you are looking for free/cheap email plans, you can check Mailjet, or Amazon SES.

Mailer.send(options)

Mailer send function expects options object. All keys are mandatory unless stated differently.

key

type

description

from (optional)

string

if you want to override default sender

to

string

comma separated emails of recipients

html

string

body of the message, will be parsed with renderer

subject

string

subject of the message, will be parsed with renderer

variables (optional)

object

variables to use in html and subject when parsing the template

baseTemplate (optional)

string

optional base template to wrap the html, needs to include {{email_body}} which will be replaced with parsed html

Sending your first email

In the previous step we prepared Mail for sending, so sending is straightforward:

const send = await Mail.send({
  from: '"Tester Tester" <test@gmail.com>', // optional
  to: 'dan@radenkovic.org, bogdan@radenkovic.org',
  subject: 'Sample Subject',
  html: '<div>Body of the message</div>',
})

And that's it!

Sending email with variables

Most of the time, you want to include some dynamic data in email subject, or email body. Mailer module supports templating thanks to mustache:

const send = await Mail.send({
  to: 'dan@radenkovic.org',
  subject: 'Hello {{username}}',
  html: '<div>Hi {{firstname}} {{lastname}}</div>',
  variables: {
    username: 'dan',
    firstname: 'Dan',
    lastname: 'Radenkovic'
  }
})

This will result sending email with subject Hello dan, and body <div>Hi Dan Radenkovic</div>.

Sending email with base template

Often, you want to have consistent header and footer in email, so you design a base template, and you inject different messages in it. To send such email, you just need to pass baseTemplate string, which has to include {{{email_body}}} (notice that it's wrapped in three curly braces so html does not get escaped) variable, which will be replaced with parsed html of the email. Base template can use passed variables too.

const send = await Mail.send({
  to: 'dan@radenkovic.org',
  subject: 'I has template',
  baseTemplate: '<html>from base template I say {{{email_body}}}</html>'
  html: '<div>Hi {{firstname}} {{lastname}}</div>',
  variables: {
    username: 'dan',
    firstname: 'Dan',
    lastname: 'Radenkovic'
  }
})

This will result sending email body <html>from base template I say <div>Hi Dan Radenkovic</div></html>.

Replacing the renderer

If you want to use more robust template renderer, you can pass renderer function when instantiating the mailer class:

const CustomRenderEmails = new Mailer({
  ... // omitted for clarity
  renderer: (content, variables) => {
    // implement some variable parsing here
    return content // dummy renderer, ignores variables and returns content
  }
})

The renderer function should accept two arguments: content (string with some tags to be replaced), and variables, object with variables and it should return parsed string.

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