In this file, you first imported the required module from @nestjs/common, mongoose, and @nestjs/mongoose. You also imported an interface named Post and a data transfer object CreatePostDTO. In the constructor, you added @InjectModel(‘Post’), which will inject the Post model into this BlogService class. With that, you will now be able to use this injected model to retrieve all posts, fetch a single post, and carry out other database-related activities.
Build and Authenticate a Node.js App with JSON Web Tokens
The first one is the Service role, when a component contains some business logic. The second one is the Repository role, when a component abstracts away the interaction with databases. In the api-gateway app, create the auth module responsible for handling authentication-related requests like sign up. Configure the Kafka client using ClientsModule from the @nestjs/microservices package in the auth module. Besides these seven runtime dependencies, we also needed to define two development dependencies on our app. The first one, @types/node, provides TypeScript definition for the Node.js API.
- We will test our newly developed REST API with Postman and ensure we have the right data.
- With the documentation, it’s straightforward to get started, and almost all your development questions have already been covered in the documentation.
- Now create a sub-directory named schemas within the initially created blog directory.
- We demonstrated how these technologies can be used together to create a scalable, reliable, and easy-to-maintain system.
- You also imported an interface named Post and a data transfer object CreatePostDTO.
- We’ll also explain the pros and cons of the framework to give you a clear picture of why companies prefer it to other Node.js frameworks.
- You’ll see how the application lets you build a simple URL shortening service in Nest and TypeScript, with a Redis backend.
Nest.js is a server-side Node.js framework that’s great for building highly testable and maintainable backend applications. You can create countless types of applications with Node.js; you’re only limited by your applications’ features. Nest.js allows developers to create components that can be injected into other components or controllers. A component usually plays one of two roles on Nest.js applications.
Serializing Classes on Nest.js
When an HTTP request is received, the routing mechanism routes it to the correct controller within NestJS. Controllers handle incoming requests and respond to the application’s client side. Each NestJS application contains at least one module, known as the root module. Nest uses the root module as a starting point to resolve the structure and relationships of the application. A module is a class that has been annotated with the @Module() decorator.
Adding the payments microservice
Any change in the database/CRM services (like SDK changes) will lead to changes in our use case. This option will break our clean architecture assumptions that use cases express the business process and that frameworks (like database and external services) are invisible to them. Services in Nest.js handle any complex business logic data manipulations for a specific purpose and return the appropriate response to the controller. NestJS has proven to be the fastest-growing TypeScript framework for building flexible, scalable, large-scale, and enterprise-ready backend applications using Node.js. Real-time streaming services are complex, with multiple levels of data streams. To create such an app, you’ll need a robust framework such as Express.js that can efficiently handle asynchronous data streams.
The good news is that TypeScript’s pros outweigh its cons for ideal use cases. Here you have successfully defined the types of data for a Post type as string values. This definition specifies that all fields will store and only accept string values. With this in place, the datatype of data that will be stored in the database will be properly controlled.
We will walk through the architecture from the inside out, or the opposite direction from the dependency rule. In this article, I will give my interpretation of how to implement this architecture in Node with NestJs. I will try to explain the different implementation considerations along the way. Like any other architecture, there are many different approaches to implement it, and each approach has its own consideration and trade-offs. This diagram is taken from the official article by Robert C. Martin.
For those who already know and use Angular, the syntax and the components that Nest.js introduces to backend development will be quite familiar. Donations to freeCodeCamp go toward our education initiatives, and help pay for servers, services, https://wizardsdev.com/en/vacancy/middle-senior-nestjs-developer/ and staff. Here, we are injecting our Post repository to communicate with our database. Then we check if the password in the DB matched what the User provided. If any of these checks fail, we return null, if not, we return the user object.
This helps you group a set of related routes and minimises code repetition. For instance, when you make an API call to /posts the controller will handle this request and return the appropriate response you specified. Nest.js automatically creates the required controller and service files for initial development.