Understanding controllers and routes in NestJS

NestJS is a Node.js framework built using TypeScript to create scalable server-side applications, focusing on routes and controllers to manage HTTP requests. This article provides a comprehensive guide on setting up NestJS projects, defining and implementing custom routes and controllers, and handling HTTP requests with parameters, payload bodies, and query parameters. The tutorial also walks through creating a project using the NestJS CLI, setting up a MySQL database with TypeORM, and implementing a Tree entity and TreeService for data management. It delves into the repository design pattern to separate business logic from data objects and discusses best practices for validating route parameters using the class-validator package. Additionally, the piece offers insights into creating DTO classes for handling request payloads and demonstrates how to extend service and entity layers to filter results based on query options. The article concludes by providing access to the complete code on GitHub and suggests using LogRocket for error tracking to enhance application performance.