Common Module for Microservices

A shared npm package containing reusable logic, classes, and middlewares used across multiple microservices in a Node.js-based microservices architecture.

📦 What’s Included

This module centralizes and exports the following utilities:

🧠 Middlewares

• validateRequest – Validates the request body using express-validator.
• errorHandler – Custom Express error handler.
• currentUser – Middleware to decode and attach the current user from JWT token.
• requireAuth – Middleware to restrict access to authenticated users only.
• NotFoundError / BadRequestError / NotAuthorizedError / RequestValidationError – Custom error classes.

📣 Events & Base Classes

• Publisher and Listener – Base classes built around NATS streaming server.
• Subjects – Enum defining event subjects.
• Events – Interfaces for event contracts (e.g., TicketCreatedEvent, OrderCancelledEvent).

🚀 Getting Started

Install

# install module
npm install @car-parts/common

Usage Example

import {
  requireAuth,
  validateRequest,
  BadRequestError,
} from '@abtickets-app/common';

app.post('/api/resource', requireAuth, validateRequest, (req, res) => {
  if (!req.body.title) {
    throw new BadRequestError('Title is required');
  }

  res.status(201).send({ success: true });
});