NodeJS mailhog client library for email end-to-end testing, written in TypeScript.

👋 Description

NodeJS client library for mailhog, based on the mailhog npm package. Mailhog is an excellent email testing tool for local development and automated end-to-end testing. While an HTTP API is offerend for implementing tests (e.g. "expect that the reset password email was retrieved"), it is very limited in its capabilities and is not well suited for writing tests. The mailhog-awesome package attempts to solve these issues by providing an API that enables developers to write simple and robust email tests.

The following functionality is provided:

• Inbox system for isolated testing (needed to run tests in parallel)
• Built-in retry logic for email retrieval
• Comprehensive TypeScript typings

🏃 Get Started

  mailhog = new MailhogClient({
    host: 'localhost',
    port: 8025,
  });

  const emails = await mailhog.getInbox('[email protected]');

A simple Jest example test-suite:

import { createTransport } from 'nodemailer';
import { MailhogClient } from './mailhog';

describe('Example Jest email test-suite', () => {
  let mailhog: MailhogClient;
  const host = 'mailhog';

  beforeAll(async () => {
    mailhog = new MailhogClient({
      host,
      port: 8025,
    });
  });

  it('Retrieve the "reset password" email', async () => {
    // Inbox email only used for this test
    const inbox = '[email protected]';

    // Clear the inbox before starting
    await mailhog.clearInbox(inbox);

    // Trigger the "reset password" email via your server's API
    const transport = createTransport({ host, port: 1025, secure: false });
    transport.sendMail({
      from: '[email protected]',
      to: inbox,
      subject: 'Reset your password',
      html: 'Please follow the link to reset your password.',
    });

    // Get the latest email
    const email = await mailhog.getLastEmail({
      from: '[email protected]',
      to: inbox,
      subject: 'Reset your password',
    });

    // Expect that a "reset password" email was received
    expect(email).toBeTruthy();

    // Clear inbox after the test has passed
    await mailhog.clearInbox(inbox);
  });
});

🔧 API

▸ getInbox(email: string): Promise‹Email[]›

Get all emails for an inbox of an email address

Parameters:

Name	Type	Description
email	string	email address

Returns: Promise‹Email[]›

---

▸ clearInbox(email: string): Promise‹true | MailhogError[]›

Clear the inbox of an email address

Parameters:

Name	Type	Description
email	string	email address

Returns: Promise‹true | MailhogError[]›

---

▸ getEmails(options: FindEmailOptions): Promise‹Email[]›

Get all emails given a set of find options

Parameters:

Name	Type	Description
options	FindEmailOptions	email find options

Returns: Promise‹Email[]›

---

▸ getAllEmails(): Promise‹Email[]›

Get all emails.

Returns: Promise‹Email[]›

---

▸ getLastEmail(options: FindEmailOptions): Promise‹Email | undefined›

Get the most recent email given the provided find options.

Parameters:

Name	Type	Default	Description
options	FindEmailOptions	{}	Email find options

Returns: Promise‹Email | undefined›

---

▸ deleteEmail(id: string): Promise‹true | MailhogError›

Delete the email with the given ID.

Parameters:

Name	Type	Description
id	string	ID of the email

Returns: Promise‹true | MailhogError›

---

▸ deleteEmails(options: FindEmailOptions): Promise‹true | MailhogError[]›

Delete all emails matching the given find options

Parameters:

Name	Type	Description
options	FindEmailOptions	email find options

Returns: Promise‹true | MailhogError[]›

---

▸ deleteAllEmails(): Promise‹true | MailhogError[]›

Delete all emails.

Returns: Promise‹true | MailhogError[]›

---

▸ releaseEmail(id: string, config: ReleaseSmtpConfig): Promise‹true | MailhogError›

Releases the mail with the given ID using the provided SMTP config.

Parameters:

Name	Type	Description
id	string	message ID
config	ReleaseSmtpConfig	SMTP configuration

Returns: Promise‹true | MailhogError›

---

▸ releaseEmails(config: ReleaseSmtpConfig, options: FindEmailOptions): Promise‹true | MailhogError[]›

Release all emails that match the given find options using the provided SMTP config.

Parameters:

Name	Type	Description
config	ReleaseSmtpConfig	SMTP configuration
options	FindEmailOptions	Email find options

Returns: Promise‹true | MailhogError[]›

---

▸ releaseAllEmails(config: ReleaseSmtpConfig): Promise‹true | MailhogError[]›

Release all emails using the provided SMTP config.

Parameters:

Name	Type	Description
config	ReleaseSmtpConfig	SMTP configuration

Returns: Promise‹true | MailhogError[]›

---

▸ encode(str: string, encoding: string, charset?: string, lineLength?: number): string

Encodes a String in the given charset to base64 or quoted-printable encoding.

Parameters:

Name	Type	Description
str	string	String to encode
encoding	string	base64/quoted-printable
charset?	string	Charset of the input string (default: 'utf8')
lineLength?	number	Soft line break limit (default: 76)

Returns: string

---

▸ decode(str: string, encoding: string, charset?: string): string

Decodes a String from the given encoding and outputs it in the given charset.

Parameters:

Name	Type	Description
str	string	String to decode
encoding	string	base64/quoted-printable
charset?	string	Charset to use for the output (default: 'utf8')

Returns: string

---

▸ extractUrls(str: string): string[]

Extract all URLs from a string

Parameters:

Name	Type	Description
str	string	string to extract all URLs from

Returns: string[]

🚨 Known Issues

• The "bcc" field is not retrieved by mailhog.
• Not optimized for performance on large sets of emails: Due to the limited functionality offered by the mailhog web API, the mailhog-awesome package has to perform operations that have a sub-optimal runtime complexity, which will be noticeable for larger amounts of emails. As the primary focus of this package is the implementation of end-to-end email tests, this can be easily avoided by properly isolating test suites and clearing the inbox after a test has finished.

🙏 Contributing

You are welcome to contribute to the mailhog-awesome GitHub repository! All infos can be found here: How to contribute

📖 License

Mailhog-awesome is MIT licensed.