Variable values have certain types. In fact, you can cast a value of one type to the other. If you do it explicitly, it is type casting (also called explicit coercion). If it happens in the background when you are trying to perform an operation on types that do not match, it is called coercion (sometimes referred to […]
In this part of the Express TypeScript tutorial, we cover using a MongoDB database. To do that properly, we also learn the concept of environment variables. Since we follow the MVC pattern, we introduce the idea of a model. Just as in the previous part of the tutorial, all of the code from this part […]
Hello! In this new series, we build a RESTful application with TypeScript Express. The course is going to cover the fundamental concepts of the express framework and tools like MongoDB. Some basic knowledge of TypeScript would be useful, as we focus on Express here. I will update the repository with the current state of the […]
Hello! Today we tackle a very interesting topic, which is recursion. The article describes its main principles and dives deeper to uncover how does it work under the hood of the language, covering execution context and the call stack. Let’s go! JavaScript recursion Recursion An act of a function calling itself. Recursion is used to solve […]
There is a high chance that you’ve stumbled across the JavaScript eval function. It is a common knowledge that in JavaScript, eval is something that is a bad practice. Have you ever wondered how it works and why exactly a lot of people discourage it? This article covers that and presents some real-life usage of the eval […]
Mistakes happen. That’s a given. According to Murphy’s law, whatever can go wrong, will go wrong. Your job, as a programmer, is to be prepared for that fact. You have a set of tools that are prepared to do precisely that. In this article, we go through them and explain how they work. An error […]
In this article, we explain what Cross-Origin Resource Sharing (CORS) is and how to avoid errors associated with it and the Access-Control-Allow-Origin header. This includes describing it both from the viewpoint of the frontend and the backend. CORS: Cross-Origin Resource Sharing Cross-Origin Resource Sharing (CORS) is a mechanism allowing (or disallowing) the resources to be […]
Nowadays, JavaScript is often used to make Ajax requests. There are a lot of libraries that can do that for us, for example, axios or jQuery. Both of them use XMLHttpRequest (XHR). It differs from the relatively new Fetch API that was introduced a few years ago. This article explains both of them and points out their […]
In this article, we cover ways to join strings. Even though it includes old methods of concatenating strings, we focus on template literals. Here you can learn how they work and how to expand their functionality with tags. Let’s go! Before template literals Back in the days, we didn’t have template literals and to merge […]
The array is a popular concept across many programming languages. At first glance, arrays work in the same way, but the JavaScript array differs from languages like C++. The article explains the basics of how JavaScript arrays work under the hood. It includes what are indexes and what is a maximum size of an array. Aside […]
IndexedDB is another API meant for client-side storage. It is good for storing a significant amount of data, including files. IndexedDB is more suitable than WebStorage suitable for keeping structured data, and definitely more adequate for that than cookies. In this article, we go through the main concepts of IndexedDB. Basic concepts of IndexedDB IndexedDB is […]