How to Create a Custom Repository with NestJS, TypeORM, and PostgreSQL

Discover how to effectively create a custom repository using `NestJS` and `TypeORM` with PostgreSQL, following the updated methods after the deprecation of the @EntityRepository decorator.
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How to Create a Custom Repository with NestJS, TypeORM, and PostgreSQL

If you've been exploring NestJS and TypeORM for your PostgreSQL projects, you might have encountered the deprecation of the @EntityRepository decorator. This shift could create confusion, especially if you're trying to maintain or enhance your existing applications with custom repository patterns. Let's break down how to create a custom repository in NestJS using TypeORM without relying on the deprecated features.

Understanding the Custom Repository

In many applications, repositories serve as a bridge between your application logic and the database. They encapsulate data access logic, allowing you to define methods that interact with your database entities. With NestJS and TypeORM, it’s essential to structure your custom repository correctly to keep your code clean and maintainable.

Steps to Create a Custom Repository

Set Up Your Entity: Ensure you have defined your entity correctly. In this example, we will use an Appointment entity.

Create the Custom Repository:

Instead of using @EntityRepository, you can extend the Repository class from TypeORM.

Register the Repository:

Make sure to register your custom repository within your module for dependency injection.

Here’s a detailed explanation of how you can implement this:

Step-by-Step Implementation

1. Define Your Entity

First, ensure that you have your entity set up. Here is a simple Appointment entity:

[[See Video to Reveal this Text or Code Snippet]]

2. Create the Custom Repository

Now, we’ll create a custom repository for the Appointment entity by extending the TypeORM Repository class:

[[See Video to Reveal this Text or Code Snippet]]

Here’s an overview of the code:

Constructor: The constructor is set up to utilize the DataSource provided by TypeORM.

Custom Method: The findOneByUUID method is defined, which allows you to retrieve an appointment based on its UUID.

3. Register Your Custom Repository

In your module file, import and register your custom repository using the TypeOrmModule:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Using the above steps, you can create a functional and maintainable custom repository in NestJS with TypeORM and PostgreSQL. This approach not only helps in keeping your application clean but also adheres to current standards following the deprecation of the @EntityRepository.

Feel free to extend your custom repository by adding more methods as per your specific application needs. Happy coding!