readme.md for @push.rocks/smartmail

A unified format for representing and dealing with emails, with support for attachments, email validation, dynamic templating, and wire format serialization for microservice communication.
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Install
pnpm add @push.rocks/smartmail
Features
📧 Advanced Email Address Validation - Validate email format, check for disposable/free domains, verify MX records, and detect role accounts
📝 Rich Email Representation - Create emails with multiple recipients (to/cc/bcc), attachments, HTML content, and custom headers
🎨 Template Support - Use mustache templates for dynamic content in subject, body, and HTML
📨 MIME Formatting - Convert emails to standard MIME format compatible with nodemailer and other sending libraries
⚡ Caching & Performance - Smart caching of DNS lookups for better performance
🔗 Creation Object Reference - Associate arbitrary typed data with emails for tracking and context preservation
🔄 Fluent Chainable API - All methods return 
this for elegant method chaining
📡 Wire Format Serialization - JSON serialization with base64 attachments for microservice communication
🌐 Wire Protocol Classes - 
WireTarget and 
WireParser for client-server email service architecture
Usage
Importing the Module
import {
  Smartmail,
  EmailAddressValidator,
  WireTarget,
  WireParser,
  createMessageId,
  createTimestamp
} from '@push.rocks/smartmail';
🔗 Fluent Chainable API
All mutation methods return 
this, enabling elegant method chaining:
const response = await new Smartmail({
  from: 'sender@example.com',
  subject: 'Hello {{name}}',
  body: 'Welcome to our service!'
})
  .addRecipient('user@example.com')
  .addRecipient('manager@example.com', 'cc')
  .addRecipients(['team1@example.com', 'team2@example.com'], 'bcc')
  .setReplyTo('support@example.com')
  .setPriority('high')
  .addHeader('X-Campaign-ID', '12345')
  .applyVariables({ name: 'John' })
  .sendTo(wireTarget);  // Send directly to a WireTarget
📧 Email Address Validation
Basic Email Validation
const emailValidator = new EmailAddressValidator();
const result = await emailValidator.validate('user@example.com');
console.log(result);
/*
{
  valid: true,           // Overall validity
  formatValid: true,     // Email format is valid
  localPartValid: true,  // Local part (before @) is valid
  domainPartValid: true, // Domain part (after @) is valid
  mxValid: true,         // Domain has valid MX records
  disposable: false,     // Not a disposable email domain
  freemail: false,       // Not a free email provider
  reason: 'Email is valid'
}
*/
Advanced Validation Options
const validator = new EmailAddressValidator({
  skipOnlineDomainFetch: true,  // Use only local domain list
  cacheDnsResults: true,        // Cache DNS lookups
  cacheExpiryMs: 7200000        // Cache expires after 2 hours
});
// Validate each part separately
const isValidFormat = validator.isValidEmailFormat('user@example.com');
const isValidLocalPart = validator.isValidLocalPart('user');
const isValidDomain = validator.isValidDomainPart('example.com');
// Check for disposable or free email providers
const result = await validator.validate('user@gmail.com');
if (result.freemail) {
  console.log('This is a free email provider');
}
Checking for Disposable Emails and Role Accounts
const validator = new EmailAddressValidator();
// Check if an email is from a disposable domain
const isDisposable = await validator.isDisposableEmail('user@tempmail.com');
// Check if an email is a role account (info@, support@, admin@, etc.)
const isRole = validator.isRoleAccount('support@example.com');
// Get MX records for a domain
const mxRecords = await validator.getMxRecords('example.com');
// ['mx1.example.com', 'mx2.example.com']
📝 Creating and Using Smartmail Objects
Basic Email Creation
const email = new Smartmail({
  from: 'sender@example.com',
  to: ['recipient@example.com'],
  subject: 'Hello from SmartMail',
  body: 'This is a plain text email'
});
Using Creation Object Reference
Associate any typed data with your email for tracking and context preservation:
interface OrderNotification {
  orderId: string;
  customerName: string;
  items: string[];
  total: number;
}
const orderEmail = new Smartmail<OrderNotification>({
  from: 'orders@example.com',
  to: ['customer@example.com'],
  subject: 'Your Order #{{orderId}} Confirmation',
  body: 'Thank you for your order, {{customerName}}!',
  creationObjectRef: {
    orderId: '12345',
    customerName: 'John Smith',
    items: ['Product A', 'Product B'],
    total: 99.95
  }
});
// Later, retrieve the original reference data
const orderData = orderEmail.getCreationObject();
console.log(`Processing email for order ${orderData.orderId}`);
// Use the reference data for templating
const subject = orderEmail.getSubject(orderData);  // "Your Order #12345 Confirmation"
Template Variables in Subject and Body
const template = new Smartmail({
  from: 'notifications@example.com',
  subject: 'Welcome, {{name}}!',
  body: 'Hello {{name}},\n\nYour account ({{email}}) has been activated.',
  htmlBody: '<h1>Welcome, {{name}}!</h1><p>Your account (<strong>{{email}}</strong>) has been activated.</p>'
});
// Apply template variables when retrieving content
const subject = template.getSubject({ name: 'John Doe' });
const plainBody = template.getBody({ name: 'John Doe', email: 'john@example.com' });
// Or apply variables directly (modifies in place, chainable)
template.applyVariables({ name: 'John Doe', email: 'john@example.com' });
Adding Attachments
import { SmartFile } from '@push.rocks/smartfile';
const email = new Smartmail({
  from: 'sender@example.com',
  to: ['recipient@example.com'],
  subject: 'Report Attached',
  body: 'Please find the attached report.'
});
const report = await SmartFile.fromFilePath('/path/to/report.pdf');
const image = await SmartFile.fromFilePath('/path/to/image.png');
email
  .addAttachment(report)
  .addAttachment(image);
Converting to MIME Format
const email = new Smartmail({
  from: 'sender@example.com',
  to: ['recipient@example.com'],
  subject: 'Hello {{name}}',
  body: 'Text version: Hello {{name}}',
  htmlBody: '<p>HTML version: Hello <strong>{{name}}</strong></p>',
  validateEmails: true
});
const mimeObj = await email.toMimeFormat({ name: 'John' });
// Use with nodemailer or other email sending libraries
📡 Wire Format Serialization
Smartmail provides JSON serialization for transmitting emails between microservices. Attachments are automatically encoded as base64.
Serializing to JSON
const email = new Smartmail({
  from: 'sender@example.com',
  to: ['recipient@example.com'],
  subject: 'Wire Format Test',
  body: 'This email can be serialized!'
})
  .addAttachment(someFile)
  .setPriority('high');
// Serialize to JSON object
const jsonObject = email.toObject();
// Serialize to JSON string
const jsonString = email.toJson();
Deserializing from JSON
// From JSON object
const email1 = Smartmail.fromObject(jsonObject);
// From JSON string
const email2 = Smartmail.fromJson(jsonString);
// Attachments are automatically reconstructed from base64
console.log(email2.attachments[0].contentBuffer);
🌐 Wire Protocol Classes
For microservice architectures, smartmail provides 
WireTarget and 
WireParser classes to handle client-server communication.
WireTarget (Client/SaaS Side)
The 
WireTarget is used by your SaaS application to communicate with an SMTP service:
import { WireTarget, Smartmail } from '@push.rocks/smartmail';
// Configure the target endpoint
const smtpTarget = new WireTarget({
  endpoint: 'https://smtp-service.example.com/api/wire',
  authToken: 'your-secret-token'
});
// Submit SMTP settings (extensible - add any custom settings)
await smtpTarget.updateSettings({
  smtp: {
    host: 'smtp.example.com',
    port: 587,
    secure: true,
    username: 'user',
    password: 'pass'
  },
  defaultFrom: 'noreply@example.com',
  customSetting: 'custom-value'  // Extensible!
});
// Send an email using fluent API
const response = await new Smartmail({
  from: 'sender@example.com',
  subject: 'Hello {{name}}',
  body: 'Welcome!'
})
  .addRecipient('user@example.com')
  .setPriority('high')
  .applyVariables({ name: 'John' })
  .sendTo(smtpTarget);
console.log(`Sent! Delivery ID: ${response.deliveryId}`);
// Check delivery status
const status = await smtpTarget.getStatus(response.deliveryId);
console.log(`Status: ${status.status}`);  // 'queued' | 'sending' | 'sent' | 'failed'
// List emails in a mailbox
const inbox = await smtpTarget.listMailbox('INBOX', { limit: 10, offset: 0 });
console.log(`Found ${inbox.total} emails`);
// Fetch a specific email
const fetchedEmail = await smtpTarget.fetchEmail('INBOX', 'email-id-123');
WireParser (Server/SMTP Side)
The 
WireParser is used by your SMTP service to handle incoming wire messages:
import { WireParser, createMessageId, createTimestamp } from '@push.rocks/smartmail';
const parser = new WireParser({
  // Handle email send requests
  async onMailSend(email, options) {
    const mimeFormat = await email.toMimeFormat();
    await transporter.sendMail(mimeFormat);
    return {
      type: 'mail.send.response',
      messageId: createMessageId(),
      timestamp: createTimestamp(),
      success: true,
      deliveryId: generateDeliveryId()
    };
  },
  // Handle settings updates
  async onSettingsUpdate(settings) {
    if (settings.smtp) {
      configureSmtpTransport(settings.smtp);
    }
    // Handle custom settings
    if (settings.customSetting) {
      handleCustomSetting(settings.customSetting);
    }
    return {
      type: 'settings.update.response',
      messageId: createMessageId(),
      timestamp: createTimestamp(),
      success: true
    };
  },
  // Handle mailbox list requests
  async onMailboxList(mailbox, options) {
    const emails = await getEmailsFromMailbox(mailbox, options);
    return {
      type: 'mailbox.list.response',
      messageId: createMessageId(),
      timestamp: createTimestamp(),
      mailbox,
      emails: emails.map(e => e.toObject()),
      total: emails.length
    };
  },
  // Handle email fetch requests
  async onMailFetch(mailbox, emailId) {
    const email = await getEmailById(mailbox, emailId);
    return {
      type: 'mail.fetch.response',
      messageId: createMessageId(),
      timestamp: createTimestamp(),
      email: email ? email.toObject() : null
    };
  },
  // Handle status check requests
  async onMailStatus(deliveryId) {
    const status = await getDeliveryStatus(deliveryId);
    return {
      type: 'mail.status.response',
      messageId: createMessageId(),
      timestamp: createTimestamp(),
      deliveryId,
      status: status.state
    };
  }
});
// Express route handler example
app.post('/api/wire', async (req, res) => {
  const responseJson = await parser.parseAndHandle(JSON.stringify(req.body));
  res.json(JSON.parse(responseJson));
});
Wire Protocol Message Types
// All available message type interfaces
import type {
  IWireMessage,
  IMailSendRequest,
  IMailSendResponse,
  IMailboxListRequest,
  IMailboxListResponse,
  IMailFetchRequest,
  IMailFetchResponse,
  IMailStatusRequest,
  IMailStatusResponse,
  ISettingsUpdateRequest,
  ISettingsUpdateResponse,
  IWireSettings,
  ISmtpSettings,
  TWireMessage  // Union type for type discrimination
} from '@push.rocks/smartmail';
// Helper functions
import { createMessageId, createTimestamp } from '@push.rocks/smartmail';
API Reference
EmailAddressValidator
Constructor Options
Option
Type
Default
Description
skipOnlineDomainFetch
boolean
false
Skip fetching domain list from online source
cacheDnsResults
boolean
true
Cache DNS lookup results
cacheExpiryMs
number
3600000
Cache expiry in milliseconds (1 hour)
Methods
Method
Returns
Description
validate(email)
Promise<IEmailValidationResult>
Full validation with format, MX, and domain checks
isValidEmailFormat(email)
boolean
Check if email format is valid
isValidLocalPart(localPart)
boolean
Validate local part (before @)
isValidDomainPart(domainPart)
boolean
Validate domain part (after @)
checkMxRecords(domain)
Promise<any>
Check MX records for a domain
getMxRecords(domain)
Promise<string[]>
Get MX record hostnames for a domain
isDisposableEmail(email)
Promise<boolean>
Check if email is from a disposable domain
isRoleAccount(email)
boolean
Check if email is a role account
Smartmail
Constructor Options
Option
Type
Default
Description
from
string
required
Email address of sender
to
string[]
[]
Array of primary recipient email addresses
cc
string[]
[]
Array of CC recipient email addresses
bcc
string[]
[]
Array of BCC recipient email addresses
subject
string
required
Email subject line (supports templates)
body
string
required
Plain text email body (supports templates)
htmlBody
string
undefined
HTML version of email body (supports templates)
replyTo
string
undefined
Reply-to email address
headers
Record<string, string>
{}
Custom email headers
priority
'high' | 'normal' | 'low'
'normal'
Email priority level
validateEmails
boolean
false
Validate all emails before MIME conversion
creationObjectRef
T
undefined
Reference data of any type (generic)
Methods (All chainable methods return 
this)
Method
Returns
Description
addRecipient(email, type?)
this
Add a single recipient (to/cc/bcc)
addRecipients(emails, type?)
this
Add multiple recipients
setReplyTo(email)
this
Set reply-to address
setPriority(priority)
this
Set email priority
addHeader(name, value)
this
Add custom header
addAttachment(smartfile)
this
Add a file attachment
applyVariables(variables)
this
Apply template variables in place
getSubject(data?)
string
Get processed subject with template variables
getBody(data?)
string
Get processed plain text body
getHtmlBody(data?)
string | null
Get processed HTML body
getCreationObject()
T
Get the stored reference data
validateAllEmails()
Promise<Record<string, boolean>>
Validate all email addresses
toMimeFormat(data?)
Promise<object>
Convert to MIME format object
toObject()
ISmartmailJson<T>
Serialize to JSON object
toJson()
string
Serialize to JSON string
sendTo(target)
Promise<IMailSendResponse>
Send to a WireTarget
Static Methods
Method
Returns
Description
Smartmail.fromObject(obj)
Smartmail<T>
Create from JSON object
Smartmail.fromJson(json)
Smartmail<T>
Create from JSON string
WireTarget
Constructor Options
Option
Type
Description
endpoint
string
URL of the SMTP service endpoint
authToken
string
Optional authentication token
Methods
Method
Returns
Description
sendEmail(email)
Promise<IMailSendResponse>
Send an email through this target
updateSettings(settings)
Promise<ISettingsUpdateResponse>
Update settings on the target
listMailbox(mailbox, options?)
Promise<IMailboxListResponse>
List emails in a mailbox
fetchEmail(mailbox, emailId)
Promise<Smartmail | null>
Fetch a specific email
getStatus(deliveryId)
Promise<IMailStatusResponse>
Check delivery status
WireParser
Constructor
new WireParser(handlers: IWireHandlers)
Handler Interface
interface IWireHandlers {
  onMailSend?: (email: Smartmail, options?) => Promise<IMailSendResponse>;
  onMailboxList?: (mailbox: string, options?) => Promise<IMailboxListResponse>;
  onMailFetch?: (mailbox: string, emailId: string) => Promise<IMailFetchResponse>;
  onMailStatus?: (deliveryId: string) => Promise<IMailStatusResponse>;
  onSettingsUpdate?: (settings: IWireSettings) => Promise<ISettingsUpdateResponse>;
}
Methods
Method
Returns
Description
parse(json)
TWireMessage
Parse a wire message from JSON string
handle(message)
Promise<IWireMessage>
Handle a wire message and return response
parseAndHandle(json)
Promise<string>
Parse and handle in one step
License and Legal Information
This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the license file within this repository.
Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.
Trademarks
This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH and are not included within the scope of the MIT license granted herein. Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines, and any usage must be approved in writing by Task Venture Capital GmbH.
Company Information
Task Venture Capital GmbH
Registered at District court Bremen HRB 35230 HB, Germany
For any legal inquiries or if you require further information, please contact us via email at hello@task.vc.
By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.