When designing a database, the tables we define often relate to each other. Managing those relationships is one of the essential parts of working with databases. The previous article taught us how to use raw SQL queries to set up our NestJS project to work with PostgreSQL. In this article, we go a step further […]
Object-Relational Mapping (ORM) libraries can often help us write our code faster. The ORM allows us not to write raw SQL. Instead, we can manipulate the data using an object-oriented paradigm. Using ORM can ease the learning curve of working with databases because we don’t need to go deep into learning SQL. Instead, we write […]
With feature flags (also referred to as feature toggles), we can modify our application’s behavior without changing the code. In this article, we explain the purpose of feature flags. We also show how to implement them ourselves and discuss the pros and cons. You can find the code from this article in this repository. The […]
So far in this series, we’ve defined many different modules that can group provides and controllers. None of them was customizable, though. In this article, we learn how to create dynamic modules that are customizable, making them easier to reuse. While doing that, we rewrite some of our old code to use dynamic modules. If […]
Every automated test that we write should be deterministic. One of the things we need to do to achieve that is to make our frontend tests independent of the backend. Besides mocking REST API requests, we also need to learn how to mock a WebSocket connection. In this article, we create a simple backend application and […]
One of the most crucial things about writing tests is that they should be deterministic. A particular test should always succeed or always fail. To achieve that, we sometimes need to mock parts of our environment when testing. A good example can be a function that relies on pseudo-random numbers. Besides the above, we also […]
When working with relational databases, we define the structure of the data rather strictly. For example, we need to specify the format of every table along with fields, relations, indexes, and other structures. By doing that, we also tell the database how to validate the incoming data. It is crucial to think about the structure […]
The NestJS team officially announced NestJS 9 on July 8th. One of its features is Read-Eval-Print-Loop (REPL) implementation. It is an environment that allows us to interact with our NestJS application through the terminal. In this article, we go through how to set up REPL with NestJS. We also use features built into NodeJS to […]
For a long time, TypeORM seemed to have a reputation of being somewhat stagnant. Lately, they stepped up their game, though, and started releasing many new versions. When doing that, they introduced a large number of breaking changes. In this article, we go through the most significant differences between 0.2.x and 0.3.x versions so far […]
Writing unit and integration tests is a great way to verify the business logic in our code. Unfortunately, it might not be enough to ensure that our application works as expected in a real-life scenario. When hundreds, thousands, or millions of users use our API, it strains it. We simulate the above circumstances through performance […]
