NestJS Fundamentals by Building a Spotify Clone

Introduction to the Course

• Instructor: Alie
• Course Objective: Learn NestJS by building the backend of a Spotify clone
  • NestJS: Framework for building efficient, scalable Node.js web applications
  • Skills Learned: Database design, REST APIs, deployment to production

What is NestJS?

• Built on: Node.js, ExpressJS, TypeScript
• Unique Architecture: Uses Angular concepts for easier organization and contribution
• Main Components: Controllers, Providers, Modules, Middleware, Exception Filters, Pipes, Guards, Interceptors, Custom Decorators
• Motivation: Solves the architectural issues of large Node.js applications by providing a clear structure
• Documentation: Offers a well-defined structure for backend applications

Setting Up a Project

• Installation: npm install -g @nestjs/cli to install NestJS CLI
• Creating a Project: nest new project-name
• Running the Project: npm run start:dev
• Default Port: 3000

Project Structure

• Main Files: main.ts, app.module.ts, app.controller.ts, app.service.ts
• Modules: Each module consists of controllers, services, and providers
• Development Workflow: npm run start:dev

Building a Spotify Clone

Project Setup

1. Install Dependencies: @nestjs/cli, nestjs, express, typescript
2. Create New Project: nest new spotify-clone

Creating Modules and Controllers

• Example Command: nest g module songs, nest g controller songs --no-spec, nest g service songs
• Define Routes: Use decorators like @Get(), @Post() in controllers
• Test Endpoints: Use tools like Postman or VS Code Rest Client

Integrating with a Database (PostgreSQL)

• Install ORM: npm install @nestjs/typeorm @nestjs/config pg typeorm
• Setup Database: Configure TypeOrmModule in app.module.ts
• Database Migrations: Use TypeORM for data management
• Create Entities: Use decorators like @Entity(), @Column()

Creating and Using Service Methods

• Service Methods: Methods to interact with database e.g. findAll, findOne, create, update, delete
• Dependency Injection: Inject services into controllers to handle requests
• Testing: Use .spec.ts files for unit tests with Jest

Authentication and Authorization

• User Module: Create users and manage authentication
• JWT: Use @nestjs/jwt for token-based authentication
• Encryption: Use bcrypt for password hashing
• Guards: Implement guards for roles and permissions

Error Handling and Validation

• Pipes: Use pipes for validation and transformation
• Exception Filters: Customize error handling globally or locally

Middleware and Interceptors

• Middleware: Pre-process requests (e.g., logging, authentication)
• Interceptors: Transform responses before sending them to the client
• Example: Custom Logger Middleware

Advanced Topics

• GraphQL Integration: Use @nestjs/graphql and Apollo Server
• WebSockets: Real-time communication using @nestjs/websockets and Socket.IO
• Microservices: Build scalable microservices architecture

Deployment

• Production Setup: Docker, CI/CD pipelines
• Hosting Providers: e.g., Heroku, AWS, DigitalOcean
• Environment Variables: Manage with @nestjs/config

Conclusion

• Final Thoughts: Understanding of building, deploying, and maintaining a NestJS application
• Continuous Learning: Keep up with NestJS updates and community practices
• Practice: Implementing real-world projects for hands-on learning

Additional Notes

• Code Format: Follow best practices for code formatting and structure
• Documentation: Maintain and update API documentation regularly

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References:

• NestJS Official Documentation
• TypeORM Documentation
• PostgreSQL Official Site

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