@tixvibe/common Documentation

The @tixvibe/common library is a shared library for the TixVibe microservices architecture. It provides reusable code and abstractions that ensure consistency and reduce duplication across services. This includes base classes for event handling, middleware, and shared utilities.

@tixvibe/common NPM

TixVibe Monorepo

Features

1. Event-Driven Communication

The library includes base classes for implementing an event-driven architecture using NATS Streaming:

• Base Publisher: Abstracts the logic for publishing events.
• Base Listener: Provides a consistent way to listen to events with automatic acknowledgment and error handling.

2. Shared Models and DTOs

Defines shared TypeScript models and Data Transfer Objects (DTOs) used by multiple services, ensuring consistent data structures across the microservices.

3. Middleware Utilities

Reusable Express.js middleware for common tasks such as:

• Authentication and authorization.
• Error handling.
• Request validation.

4. Error Handling

Custom error classes to standardize error responses, including:

• BadRequestError
• NotFoundError
• DatabaseConnectionError
• UnauthorizedError

5. TypeScript Support

Fully typed library with interfaces and types to improve developer experience and reduce runtime errors.

Installation

To use @tixvibe/common in your microservices, install it as a dependency:

npm install @tixvibe/common

Or with Yarn:

yarn add @tixvibe/common

Usage

1. Event Handling

Publisher Example

To publish an event, extend the Publisher class and define the event type:

import { Publisher, Subjects, TicketCreatedEvent } from '@tixvibe/common';

export class TicketCreatedPublisher extends Publisher<TicketCreatedEvent> {
  readonly subject = Subjects.TicketCreated;
}

const publisher = new TicketCreatedPublisher(natsClient);
await publisher.publish({
  id: '1111',
  title: 'Tomorrowland 2026',
  price: 3300,
  userId: 'stillhome',
});

Listener Example

To listen for an event, extend the Listener class and define the event type and subject:

import { Listener, Subjects, TicketCreatedEvent } from '@tixvibe/common';
import { Message } from 'node-nats-streaming';

export class TicketCreatedListener extends Listener<TicketCreatedEvent> {
  readonly subject = Subjects.TicketCreated;
  queueGroupName = 'payments-service';

  async onMessage(data: TicketCreatedEvent['data'], msg: Message) {
    console.log('Event data:', data);

    // Business logic here

    msg.ack();
  }
}

const listener = new TicketCreatedListener(natsClient);
listener.listen();

2. Middleware

Authentication Middleware

Protect routes by verifying the JWT of incoming requests:

import { requireAuth } from '@tixvibe/common';

app.get('/secure-route', requireAuth, (req, res) => {
  res.send('This route is protected');
});

Error Handling Middleware

Handle errors in a consistent format across services:

import { errorHandler, NotFoundError } from '@tixvibe/common';

app.all('*', async () => {
  throw new NotFoundError();
});

app.use(errorHandler);

3. Custom Errors

Throw standardized errors in your services for easier debugging and consistent error responses:

import { BadRequestError } from '@tixvibe/common';

if (!user) {
  throw new BadRequestError('User not found');
}

Directory Structure

tixvibe/common
├── src
│   ├── events
│   │   ├── base-listener.ts
│   │   ├── base-publisher.ts
│   │   ├── subjects.ts
│   │   ├── ticket-created-event.ts
│   │   └── ticket-updated-event.ts
│   ├── errors
│   │   ├── bad-request-error.ts
│   │   ├── custom-error.ts
│   │   ├── database-connection-error.ts
│   │   ├── not-found-error.ts
│   │   └── unauthorized-error.ts
│   ├── middleware
│   │   ├── error-handler.ts
│   │   ├── require-auth.ts
│   │   └── validate-request.ts
│   └── index.ts
├── package.json
└── tsconfig.json

License

@tixvibe/common is licensed under the MIT License. See the LICENSE file for details.