Blogs

One widely used TypeScript feature is the ability to have optional keys on objects. However, this poses a problem that becomes more significant as the system and state become more complex. Other type systems allow this problem to be circumvented. Let’s take a closer look. Before we dive-in In TypeScript (and most type systems), a type is best understood as a set of possible values. In other words, type Name = string | null; … means “Name is the set of all strings plus the value null”. This is why it is called a Sum type, or Tagged union. ...

A Year of Watching AI Closely It’s been a while since I last wrote here. This year has been intense in many ways, and as it comes to an end, I feel the need to reflect on one hard-to-ignore topic: AI, not from a hype perspective, not from a futurist angle, but from the everyday reality of actually using it — especially in engineering work. This year, I mostly focused on Anthropic models using Claude Code or Cline. ...

Today I want to talk about an interesting (though not new) idea for representing remote resources. In fact, any resource that takes some time to retrieve. But most often we talk about network resources. At the same time, we’re going to do a bit of TypeScript gymnastics. Data type for side effects The state of a remote resource can be represented in four ways: Idle - we haven’t even requested the resource yet Loading - we have requested the resource, but the operation is not yet complete Ready<D> - we have the data Error<E> - something has gone wrong So, using a discriminated union feature of TypeScript, we can create a type for this situation: ...

I’ve wanted to touch on this topic for a long time. Mainly because it aligns with a value I respect a lot. Interviews. Specifically, technical coding interviews. Let’s put on our engineering hats and think of an interview as a solution to a problem. The problem is a lack of the right person in a team. The solution is to hire that person through a series of tests. We know that solutions should be tested, but how do we test our approach to technical interviews? One cruel way is to use candidates to validate the interview strategy. A better way is to put yourself in the candidate’s shoes. ...

I built a browser extension using Elm - GoalMet - Achieve your goals. Even though Elm’s evolution is rather slow, the JS community can learn heaps from this wonderful language and its ecosystem. Here are the main reasons why I chose Elm for my side project. Stable ecosystem Everything I learned about Elm 2-3 years ago still applies. Even though I used Elm for anything substantial around two years ago, I could jump in and be productive immediately. Can you say the same about any other popular JS framework? ...

During one of my interviews in late 2023 - early 2024, a person asked me: “Who cares about the language we choose or frameworks or type system… all that matters is a working product”. I wrote about it already, but I used a clumsy analogy with building a house. Recently, however, the internet (or at least, the algorithms that take care of my YouTube feed) started buzzing with news about the problems at Boeing. ...

It seems that these days, at times of React (and similar frameworks), CSS receives less attention. However, I remember a not-so-distant past, perhaps, five years ago, when using CSS for simple UI elements was the desired approach. True, it has its limitations. But I don’t think we can discard CSS completely and rely on JavaScript driving even the most trivial elements of UI. By applying (or at least trying to apply) the CSS-first approach, we can achieve some great results without necessarily relying on JavaScript. Such UI elements as tabs (one and two), carousels, navigation menus (one and two), and a lot more - can be built with CSS only. Check out CSSUI for some inspiration. Moreover, because this is all just CSS, responsiveness is “built-in”, and developers and designers can get creative and accommodate different scenarios. ...

I recently had a conversation about why I insist that JavaScript (and especially TypeScript) developers should learn from Rescript, Elm, Go, Rust, and other languages. A person asked me: “Who cares? Users don’t care what language you use to build your product. Often the business doesn’t care either! There are plenty of companies with tons of spaghetti code, and they sell their products well! So why bother?” Well, I couldn’t spontaneously say why I care. But I kept thinking about the chat and decided to write my answer in this post. ...

A great product experience is when the product works as expected in the scenario it was designed for, and communicates with users in a meaningful way. As developers, we cannot control how and where our product will be used, or the user input. But we have the tools to guard the flow from unexpected inputs. In this post, I want to give two pieces of advice for people working in the JS ecosystem on how to create better programs. ...

JavaScript is a dominant language for building web applications. I’ve been using it for a very long time. However, in my opinion, it just doesn’t cut it any more. Luckily, there are some compelling alternatives. JavaScript: A Dominant Yet Flawed Language JavaScript offers a quick and cheap solution for building web applications in the short term. However, in the long run, its design quirks and inherent flaws will work against its users. JavaScript is ignorant and designed to handle any input without complaint, which leads to its quirky behaviour and unpredictability. I wrote about it in my previous post. ...