NestJS CLI Overview and Basic Application Creation

Introduction to NestJS

• NestJS: A framework for building efficient and scalable Node.js server-side applications.
• TypeScript Support: Fully supports TypeScript providing a significant advantage.
• Philosophy and Influence: Inspired by projects like Angular, React, and Vue.

Getting Started with NestJS CLI

• Installation:
  • Install NestJS CLI globally on your system.
  • Use nest new <project-name> to scaffold a new application.
• Project Structure:
  • Generates a basic application structure with a nest-cli.json file.
  • Includes TypeScript configurations and test cases.
  • Contains a default module with a controller and a service.

Key Components of a NestJS Application

• Main.ts:
  • Entry point of the application.
  • Bootstraps the NestJS module and starts the application on port 3000.
• Modular Structure:
  • Root module injecting other modules.
  • Controllers define routes (e.g., HTTP GET and HTTP POST).
  • Services handle data retrieval and business logic.
• Annotations: Use of @Injectable, @Controller for dependency injection and defining logic.

Application Setup and Configuration

• Running the Application:
  • Use npm run build to compile the application.
  • Start the application using npm run start.
• Configuration Files:
  • tsconfig.json: Defines TypeScript compiler options.
  • package.json: Contains scripts for testing, building, and running the application.

Advanced Features

• Linting and Formatting:
  • Use ESLint and Prettier for code quality.
  • Configuration files like .eslintrc.js manage linting rules.
• Testing:
  • Unit tests and E2E tests are set up to ensure functionality.
• Development Tools:
  • Use Nodemon for automatic server restarts during development.

Creating and Managing Modules

• Basic Module Creation:
  • Example of creating a UserModule with its own controllers and services.
• Routing:
  • Define specific routes within controllers (e.g., /user, /hello).
• Interceptors, Pipes, Filters, and Middleware:
  • Additional building blocks that enhance application functionality.

Conclusion

• NestJS CLI: Simplifies the process of creating and managing Node.js applications with a clean and modular approach.
• Future Topics: Further discussion on interceptors, pipes, filters, and middleware in NestJS.