📦 Node.js API with TypeScript & Jest

A fully tested, production‑ready Node.js API built with TypeScript, Jest, Supertest, and Express — designed to demonstrate solid engineering practices, automated testing, clean architecture, and CI/CD pipelines.

This project is part of my journey into backend engineering and automated testing. It showcases how I structure applications, write maintainable code, and ensure reliability through unit and integration tests.

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🚀 Tech Stack

• Node.js
• TypeScript
• Express
• Jest
• Supertest
• ts-jest
• tsx
• GitHub Actions (CI)
• Docker & Docker Compose

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🎯 What This Project Demonstrates

• Unit testing for isolated business logic
• Integration testing for real HTTP flows
• Mocking dependencies
• Test coverage reporting
• Clean architecture (controller → service → repository)
• Continuous Integration with GitHub Actions
• Containerization with Docker

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📁 Project Structure

├── src
│   ├── app.ts
│   ├── server.ts
│   ├── sum.ts
│   └── products
│       ├── products.controller.ts
│       ├── products.service.ts
│       ├── products.repository.ts
│       └── products.types.ts
│
├── tests
│   ├── unit
│   │   ├── sum.test.ts
│   │   └── products.service.test.ts
│   └── integration
│       └── products.routes.test.ts
│
├── jest.config.ts
├── tsconfig.json
├── Dockerfile
├── docker-compose.yml
└── package.json

🧪 Automated Tests

Unit Tests

Unit tests validate isolated logic such as services and pure functions.

• Example: products.service.test.ts
• Validates business rules
• Ensures error handling
• Uses mocks when needed
• Guarantees predictable behavior

Integration Tests

Integration tests validate real HTTP flows using Supertest.

• Example: products.routes.test.ts
• Tests endpoints end‑to‑end
• Ensures controllers, services, and repositories work together
• Validates status codes, JSON responses, and error cases

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📊 Test Coverage

Generate coverage:

npm test -- --coverage

⚙️ Available Scripts

"scripts": { "dev": "tsx watch src/server.ts", "test:dev": "jest --watchAll", "test": "jest" }

🔄 Continuous Integration (CI)

• This project includes a GitHub Actions workflow that automatically:
• Installs dependencies
• Runs all tests
• Validates code quality
• Blocks PRs if tests fail
• Workflow file: .github/workflows/ci.yml

🐳 Docker Support

Build and run the API using Docker:

docker-compose up --build

This ensures consistent execution across any environment.