Lint Codebase & Run Unit Tests (TypeScript Express App)

This repository hosts a Node.js/TypeScript Express application that demonstrates:

• Linting with ESLint
• Unit testing with Jest
• Database operations using TypeORM
• AWS Cognito for authentication
• AWS SSM for configuration
• AWS KMS for password encryption
• AWS Redis/ElastiCache for caching
• GitHub Actions CI for linting and testing
• Docker Compose for local development

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Table of Contents

1. Project Overview
2. Prerequisites
3. Installation
4. Configuration
5. Running Locally
6. Docker Compose Setup
7. Project Scripts
8. Testing
9. Linting
10. CI/CD with GitHub Actions
11. Folder Structure
12. Contributing
13. License

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Project Overview

This application is built with:

• Node.js and TypeScript for the server logic.
• Express as the web framework.
• TypeORM for database operations (MySQL/PostgreSQL/SQLite).
• AWS services:
  • Cognito for user authentication and registration.
  • SSM (Systems Manager) to store configuration securely.
  • KMS to encrypt/decrypt sensitive data.
  • SES to send emails (if needed).
  • S3 to store files (bills, logs).
  • Redis/ElastiCache for caching.
• Jest for unit tests.
• ESLint for code linting.
• Prettier for code formatting.
• Docker + docker-compose to containerize and run services locally.

Key Features

1. Authentication & Authorization Integrates with AWS Cognito for user registration, login, token refresh, and password resets.

2. Database Management Uses TypeORM to connect to a relational database. Can run in-memory SQLite for tests.

3. Caching Redis (or ElastiCache in production) is used to cache frequently accessed data and reduce database load.

4. Error Handling A centralized error-handler middleware ensures consistent, structured JSON responses for errors.

5. CI/CD GitHub Actions pipeline runs lint checks and unit tests on every push and pull request to master or develop.

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Prerequisites

1. Node.js (version 18+ recommended)
2. npm or yarn (npm comes bundled with Node)
3. Docker (if you plan to run locally with Docker)
4. AWS CLI (optional, if you plan to interact with AWS from your local machine)
5. Git for version control

Make sure you have AWS credentials set up if testing AWS functionality locally:

aws configure

Architecture Overview

Here's a high-level overview of the system architecture:

Class Diagram

Below is the class structure represented for the application:

Component Overview

This diagram explains the major components of the application:

Database Entity Diagram

Entity relationships in the database are outlined below:

HTTP Interactions

The following diagram shows typical HTTP request/response flows:

Sequence Diagram

Authentication and other flows are depicted below:

Use Case Diagram

Here’s a summary of system use cases: