Discover Nest.js, the Backend Development Framework for Frontend
Managing a large-scale application can be tedious, especially when built without a well-planned framework and strict code organization strategy. This can lead to a disaster during application maintenance and should be avoided at all costs. Typically these disasters are due to changes made to the codebase and new features as the project grows the user base. To try to avoid these problems, Nest.js was born. Created with the purpose of offering solutions to the problems of structure and strategy of organization of the code.
What is Nest.js?
Nest.js is a Node.js – based web development framework that uses TypeScript to provide a highly scalable and robust programming framework.
It takes inspiration from other popular development frameworks, such as Angular and Spring, and focuses on building highly scalable and modular backend applications, although you can also develop web applications.
It is compatible with and includes out-of-the-box integrations with a wide variety of databases and authentication systems, and you can use it with a wide variety of third-party modules to add additional functionality. Additionally, it integrates with testing and debugging tools to help test and debug your application code.
Basic elements of the application architecture
Nest.js is a web development framework that largely mimics the Angular architecture. Although it does not use Angular libraries, it has many architectural similarities, which greatly reduces the learning curve for an Angular developer.
If you are a Frontend developer of any other framework, it is still your option over traditional Backend frameworks.
Its approach is based on components. The application is divided into modules that contain related components, controllers and services. Thus facilitating the organization and maintenance of the application code.
It is based on TypeScript, which means that you can use all TypeScript features in your code like static types, classes, inheritance, readability, interfaces, decorators, etc.
Let us see below the most outstanding elements of the application architecture:
Modules
In Nest.js, apps are divided into modules, which are collections of related components, controllers, and services that work together to accomplish a specific task.
You can learn more details here.
Controllers
Classes that handle HTTP requests and return a response. Controllers are assigned to specific routes, only handling requests that match that route.
You can learn more details here.
Services
Contain business logic and can be injected into controllers or other service classes. Services are often used to interact with databases or perform other tasks that are not specific to the presentation logic.
You can learn more details here.
Pipes
Can be used to transform or validate data going into or out of an application. Pipes can be applied to the arguments of controller methods or the values of the input and output fields of an HTTP request or response.
You can learn more details here.
Guards
They are components used to protect unauthorized access paths. Guards can be used to check if a user has permission to access a given path and to take appropriate action if they don’t.
You can learn more details here.
Middleware
Middleware is code that runs between the arrival of a request and the execution of the corresponding handler. It can be used to perform tasks such as authentication or validation of data before it reaches the controller.
You can learn more details here.
Decorators
Los decoradores son funciones que se aplican a clases, métodos o propiedades y modifican su comportamiento. Nest.js incluye varios decoradores predefinidos que se pueden utilizar para realizar tareas como la asignación de rutas a controladores o la inyección de dependencias.
You can learn more details here.
In addition to these basic elements mentioned above, Nest.js can be used with a wide variety of third-party modules that provide additional functionality. These modules can include things like databases, authentication systems, and testing tools.
What are the main functionalities of Nest.js?
Here are the main features of Nest.js:
Flexible
It can be used for both web and back-end applications. although it is more popular as a back-end application.
Scalable and modular
Designed to be highly scalable and modulable, which means it can be used to build large and complex applications without sacrificing ease of use and maintainability.
Integration with databases and authentication systems
Support for a wide variety of databases and authentication systems, which means you can use Nest.js to build apps that connect to databases or use authentication mechanisms like OAuth.
Compatible with microservices
Nest.js can be used to build applications based on microservices, which means you can break the application into smaller components that can be independently deployed and scaled.
Integration with messaging systems
It can be integrated with messaging systems such as RabbitMQ and Kafka, allowing applications to communicate with each other asynchronously.
Route scheme
It uses a routing scheme to assign controllers to specific routes, which means that they will only handle requests that match that route.
Integration with testing tools
It integrates with testing tools like Jest and Mocha, making it easy to perform unit, integration, and acceptance testing.
Integration with performance analysis tools
It integrates with tools like New Relic and Application Insights, allowing you to analyze application performance and detect problems.
Integration with monitoring tools
It integrates with tools like Prometheus and Grafana, allowing you to monitor the application and collect metrics.
Integration with transaction monitoring tools
Nest.js can be integrated with tools like APM (Application Performance Monitoring) to monitor application performance and availability.
Integration with logging tools
Nest.js integrates with logging tools like Winston and Log4js, making it easy to collect and analyze log messages.
Integration with continuous integration tools
It can be integrated with tools like Jenkins and Travis CI, making it easy for continuous integration and automated deployment.
Integration with code analysis tools
It can be integrated with tools like SonarQube and Code Climate, allowing you to analyze application code and detect quality and security issues.
Integration with configuration management tools
It can be integrated with tools such as Consul and Vault, allowing you to manage application settings centrally and securely.
Integration with security tools
It can be integrated with tools such as Auth0 and Okta, allowing authentication and authorization mechanisms to be implemented quickly and securely.
Documentation and community
It has extensive documentation and an active community of developers who can help you troubleshoot and learn more about the framework.
What third-party libraries can we integrate into Nest.js?
Additionally, Nest.js comes with a wide range of built-in third-party libraries that make application development easy. Some of the most popular bookstores include:
Express
A web server development framework that provides a wide variety of tools for handling HTTP requests and sending responses.
GraphQL
A query language and toolset for working with databases and APIs more efficiently.
MongoDB
A NoSQL database that allows easy data storage and retrieval
Passport
A set of modules that make it easy to implement authentication and authorization in applications.
Socket.io
A library that allows real-time communication between the server and clients.
Hands-on | Implementing a first controller with Nest.js
Now that we’ve covered the main features and functions of Nest.js, let’s create a sample app in Nest.js.
The application will consist of a simple CRUD controller to manage a user entity. The controller will be injected with a service to manage the business logic related to the user. In turn, the service will manipulate user data through an injected user repository
This code shows the implementation of the user repository, which is in charge of saving the data and consulting it.
Note CleanCode – To simplify the article, data is stored in memory, although you should store data in a database such as MongoDB. Also, this repository layer does not implement the repository pattern by inheriting from a standard IRepository interface, although it would be recommended.
import { Injectable } from '@nestjs/common';
import { User } from './user.entity';
@Injectable()
export class UserRepository {
private users: User[] = [];
findAll(): User[] {
return this.users;
}
findOne(id: number): User {
return this.users.find(user => user.id === id);
}
create(user: User): void {
this.users.push(user);
}
update(id: number, user: User): void {
const index = this.users.findIndex(u => u.id === id);
this.users[index] = user;
}
delete(id: number): void {
this.users = this.users.filter(user => user.id !== id);
}
}To implement the service that the repository uses, we create an interface that defines the methods that we want to expose. Next, we create a service class that implements the interface and uses the repository to perform the necessary CRUD operations.
import { Injectable } from '@nestjs/common';
import { UserRepository } from './user.repository';
import { User } from './user.entity';
export interface IUserService {
findAll(): User[];
findOne(id: number): User;
create(user: User): void;
update(id: number, user: User): void;
delete(id: number): void;
}
@Injectable()
export class UserService implements IUserService {
constructor(private readonly userRepository: UserRepository) { }
findAll(): User[] {
return this.userRepository.findAll();
}
findOne(id: number): User {
return this.userRepository.findOne(id);
}
create(user: User): void {
this.userRepository.create(user);
}
update(id: number, user: User): void {
this.userRepository.update(id, user);
}
delete(id: number): void {
this.userRepository.delete(id);
}
}With the above steps in place, we can now create the controller that will need to define the controller methods that will handle HTTP requests and use the user service injected in its constructor to perform the necessary CRUD operations.
import { Controller, Get, Post, Put, Delete, Body } from '@nestjs/common';
import { UserService } from './user.service';
import { User } from './user.entity';
@Controller('users')
export class UserController {
constructor(private readonly userService: UserService) { }
@Get()
findAll(): User[] {
return this.userService.findAll();
}
@Get(':id')
findOne(id: number): User {
return this.userService.findOne(id);
}
@Post()
create(@Body() user: User): void {
this.userService.create(user);
}
@Put(':id')
update(id: number, @Body() user: User): void {
this.userService.update(id, user);
}
@Delete(':id')
delete(id: number
): void {
this.userService.delete(id);
}
}Finally, we encapsulate all this logic in its module (as we would do in Angular), which is in charge of importing the controller and the services that we have injected into the respective constructors of each class.
import { Module } from '@nestjs/common';
import { UserController } from './user.controller';
import { UserService } from './user.service';
import { UserRepository } from './user.repository';
@Module({
controllers: [UserController],
providers: [UserService, UserRepository],
})
export class UserModule { }Is it worth using Nest.js?
In conclusion, Nest.js is a powerful and flexible Node.js application framework used to build web and server applications with a focus on modularization and scale.
Its integration with TypeScript and Angular makes it an attractive option for developers looking to use modern tools and support for object-oriented programming.
Plus, its extensive community and available resources make it easy for developers to learn and use.
Overall, we could say that Nest.js is a good option to consider if you’re looking for a Node.js application framework for building high-quality web and server applications.
However, it’s important to note that Nest.js isn’t the only option available for building Node.js applications. There are many other frameworks and tools (Frameworks such as Express, Koa, Hapi, or Fastify.) that may also be suitable for your project, and it is important to evaluate the different options available and choose the one that best suits your needs and preferences.
It’s important to note that performance and scalability are important factors to consider when choosing a Node.js application framework. Some frameworks can be faster and easier to scale than others, and it’s important to evaluate these factors to make sure the framework you choose is right for your needs.
Also, it is important to consider the size and complexity of your project when choosing a framework. If your project is small and simple, a lighter, more minimalist framework may be appropriate. If it is large and complex, you may need a more robust and comprehensive framework that provides more functionality and tools.
If Nest.js for backend or web application development piques your interest, we recommend that you refer to the official Nest.js documentation for more information on how to use the framework and all of its features. You can also search online for tutorials and code samples to get an idea of how Nest.js is used in practice.