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NestJS: A Beginners Tutorial

15
Apr
2024

Are you a Web Developer looking to build efficient and scalable server-side applications? Look no further than NestJS! Whether you are an experienced developer or just starting, this beginner's tutorial will guide you through the essential concepts and practices of NestJS. From setting up your first application to understanding Dependency Injection and advanced concepts, this comprehensive tutorial will equip you with the knowledge to harness the full potential of NestJS to build modern web applications.

What is NestJS?

NestJS, also known as Nest.js or Nest, is a progressive Node.js framework designed to build scalable and maintainable server-side applications. It shines when dealing with complex, large-scale applications, providing an out-of-the-box application architecture that seamlessly incorporates a wide range of common technologies.

With its foundation in TypeScript, NestJS bolsters developer productivity and type safety, enhancing the overall development process. The framework utilizes design patterns familiar to developers, like Dependency Injection (DI), which boosts maintainability and ease of development.

Notably, NestJS supports RESTful and GraphQL APIs (Application Programming Interfaces), unit testing, and ensuring versatility in handling incoming requests. The modular approach, with a root module and the potential for additional third-party modules, helps to organize business logic and a maintainable application structure.

NestJS Core Concepts

  • Modules. The building blocks of a NestJS application. Each module typically represents a feature or functionality within your application. They are created using the @Module decorator.‍
  • Providers. Services, repositories, factories, or any other object that you want to make injectable throughout your application are considered providers. ‍
  • Controllers. Handles incoming HTTP requests and route them to the appropriate service for processing. They use decorators like @Get or @Post, to define the API endpoints.‍
  • Services. Encapsulates the core business logic of your application and promote code reuse. They shouldn't directly interact with external dependencies like databases.

NestJS Features

NestJS offers a wide range of core features that empower developers to build robust applications. These features include Dependency management, decorators for easy metadata handling, built-in support for RESTful APIs, and WebSocket integrations. This comprehensive set of features makes NestJS a top choice for developer productivity and code maintainability.

Another powerful feature of NestJS is its built-in support for microservices architecture. With NestJS, developers can easily create and manage microservices, allowing for a more scalable and distributed system. This support for microservices aligns well with modern architectural trends, making NestJS a forward-thinking choice for building applications. 

Let’s explore some other important Nest.js features that are making developers choose it for developing digital products.

NestJS Modules and Third-Party Packages

In NestJS, managing modules and third-party packages is akin to selecting the best tools and materials for creating a unique masterpiece. A NestJS developer curates modules and packages to enhance functionality with precision. This process fosters an efficient development journey, ensuring that applications are robust and tailored to precise needs.

Modules are the primary organizational units within NestJS. These self-contained modules help segregate business logic to have clear and maintainable code. The modular architecture encapsulates providers (which can be anything ranging from services to repositories) that can be easily managed and replaced when necessary.

On the other hand, third-party packages provide ready-made solutions that can be seamlessly interwoven into your NestJS application development. These packages can range from authentication tools to database integrators, designed to speed up the development process and enhance developer productivity.

Navigating through this selection, NestJS aids in assembling a coherent yet modular application structure prepared to scale.

NestJS Dependency Injection

In technical terms, Dependency Injection is a design strategy where a class receives its dependencies from external sources rather than creating them internally. Why is this brilliant? Because it simplifies the management of dependencies and coupling between components, making your server-side applications more modular, easier to test, and, quite frankly, much more maintainable.

Implementing DI in your NestJS server-side application is like piecing together a puzzle where all the pieces fit seamlessly. NestJS takes a stand with its powerful DI system that is baked into its core, allowing you to focus fully on your business logic without sweating over the nitty-gritty of object creation. Here's a simple rundown on how you can harness the benefits of DI in NestJS:

  • Define a Service. Create a service class that encapsulates the business logic or functionality you need.
  • Decorate with Injectable. Use the @Injectable() decorator to make this class a service that can be injected.
  • Register a Service. Include the service in the provider's array of a module - often the root module or any feature module it lives in.
  • Inject the Service. Inject your service into a controller or another service via the constructor, specifying the service class type.

By embracing the power of Dependency Injection, you aim to build enterprise-level, bullet-proof architectural patterns. It positions you to harness the full spectrum of NestJS' power, from handling incoming requests to shaping your application structure for a wide range of scalable and maintainable types of applications. Whether building RESTful services, GraphQL applications, or complex microservices architecture, DI is your ticket to an efficient, easy-driven development lifestyle.

NestJS Application Efficiency

As a developer, crafting an application code that stands the test of time and growth is a true challenge. NestJS equips you with tools and practices that result in clean, maintainable, and efficient applications. These are some of the principles you can harness.

  • Design Patterns. Employ proven patterns NestJS offers for unshakeable application architecture.
  • Dependency Injection. Streamline your code by decoupling components, creating a more testable and maintainable codebase.
  • Microservices Architecture. Build your Backend to be as expansive as the universe with microservices architecture, ensuring every star shines on its own yet contributes to the galaxy.

By integrating robust features, NestJS assures that whether your application code caters to a handful of users or millions, it remains responsive, maintainable, and efficient. The framework's philosophy humanizes the development process, taking the focus off the monotonous setup and into the realm of creativity and problem-solving. Here lies the beauty of NestJS: it fosters applications and environments where developers and users thrive in a symbiotic relationship.

NestJS Third-Party Modules

One of the hallmarks of NestJS is its embrace of third-party modules. This feature optimizes the framework's flexibility, allowing applications to stand on the shoulders of giants. It lets you incorporate an ORM to interact with your database or a security library to fortify your application over time.

Conveniently, importing third-party modules typically involves a few lines of code in your root or feature modules. Nest encapsulates the ease of development with third-party modules thanks to its simple installation via package managers like npm or yarn. It also provides an intuitive configuration, often through decorators or objects. Lastly, it offers access to a wide range of functionalities, from messaging queues to payment gateways.

How To Set Up NestJS?

Getting started with the installation process of NestJS is like an exciting journey toward building a well-structured and highly functional Back-End application. The setup process is simple, ensuring you can hit the ground running without unnecessary hiccups. Let's delve into the initial steps to get NestJS up and ready for your next big project.

Installing NestJS

Before we dive in, make sure you have Node.js installed, as it's the backbone that powers NestJS. With that in place, NestJS installation is just one line of code away. Fire up your terminal and run:

npm i -g @nestjs/cli

This command installs the NestJS Command Line Interface (CLI) globally on your machine, arming you with powerful commands to boost your productivity.

Creating Your First NestJS Application

With the CLI installed, creating your first NestJS application is as easy as pie. In your terminal, navigate to where you want your application to live and execute:

nest new my-first-nest-app

Replace "my-first-nest-app" with whatever you'd like to name your application. The CLI will spring into action, scaffolding your application's structure and handling the initial configurations. It'll even handpick the best libraries, so your application is ready to tackle any challenge from day one. Once the process completes, navigate into your new NestJS project's directory:

  cd my-first-nest-app

And to lift off, just type:

  npm run start

Your freshly baked NestJS application will start, and just like that, you're on the path to building something great with one of the most efficient, scalable, and popular frameworks out there.

Remember, your journey with NestJS is supported by a vibrant community of developers and an impressive array of excellent documentation, ensuring help is always available should you need it. Now, go forth and create the next amazing server-side application with NestJS!

Integrating GraphQL in NestJS Applications

NestJS and GraphQL form a synergistic pair when crafting modern, server-side applications. GraphQL shines by allowing clients to request what they need, no more, no less. NestJS facilitates the integration of this powerful query language with minimal fuss and maximum efficiency.

To set up GraphQL in NestJS, you'll need to install the required package and tools. Next, define the schema that will describe the shape of your data. Finally, implement the resolvers that bind the schema to the corresponding business logic.

This integration not only endorses cleaner and more scalable applications but also empowers developers to construct flexible solutions that are attuned to the specific requirements of front-end systems. The result is a harmonious backend that delivers what's needed for various applications, fostering an environment where developers and users form a cohesive and satisfied community.

Why Use NestJS?

One of the main reasons for choosing NestJS is its compatibility with TypeScript. By combining TypeScript's strong typing and the flexibility of JavaScript, developers can catch errors early and write cleaner, more maintainable code. Additionally, NestJS encourages using industry-standard design patterns, such as SOLID principles, which further enhance code readability and maintainability.

Moreover, NestJS provides a thriving ecosystem with a vibrant community and a rich collection of plugins and modules. This ecosystem ensures that developers can access a wide range of tools and resources to expedite their efficient development process. The active community also means developers can seek help, share knowledge, and collaborate on projects, fostering a supportive environment for NestJS users.

Conclusion

Nest is a robust framework for Software Developers who want to build efficient and scalable server-side applications. It is a top choice for developers who value productivity, code maintainability, and versatility. Its vibrant community and wide range of plugins and modules ensure access to many tools and resources, making it an exciting framework. So why wait? Install NestJS today and start building something great!