From all software development languages, JavaScript has probably the most interesting history.

Born in September 1995, as a 3-month project this language became the most popular and most used language with lots of advanced features like parallel execution (web workers and service workers), generator functions and iterators, support of WebGL, and of course, all promising WebAssembly.

A brief history of JavaScript

The most interesting feature of this language though, in my opinion, is nearly a 100% back-compatibility with the old versions! Code, written in new ES2020 syntax can be easily transpiled back to ES5 and vice-versa using tools like babel or traceour!


When it comes to writing applications using react, we end up having a huge package.json file with additional libraries that are used to manage application state and behavior. And there are so many options: Redux, Unistore, Mobx, Immerjs and so on. There is one big issue with those libraries though. They aren’t managing application state, but rather its data. You can treat all of them as an application cache level 0.

In this article, I want to introduce you to, in my opinion, one true state management library — Xstate. I will do that by writing a simple search application…


Every software developer has his/her own favorite IDE. IDEs provide us all the tooling needed to write clean, readable code faster and with fewer errors. Thanks to various hints and code completion, one does not need to remember commands and directives of programming language anymore.

However, most software developers tend to use only a few features of IDEs and rely on visual user interfaces to do most of their job, which is not fast. In this article, I will show you a few tips and tricks that I use to increase my productivity when working with an IDE.

I will…


If your application is becoming increasingly slower while you’re using it or suddenly you’re getting the “page(s) have become unresponsive” message in your browser — this might mean that you have a ‘memory leak’.

So what is memory leak?

A memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in such a way that memory which is no longer needed is not released

Imagine you’re the owner of a public swimming pool. You offer lockers for your customers to store their belongings in. However, you have some customers who never return…


At Property Finder, we’re currently going through a process of redesigning elements of our website. This has given us the opportunity to refactor and improve the existing codebase, as well as writing new code from scratch.

You can see our progress so far on the amazing new property detail page on mobile.

What made us invest in web performance?

Since July 2018, Google has modified their ranking algorithm to include website performance, meaning that faster responding websites get better SEO treatment. It therefore made sense for us to invest more in improving and optimizing product performance and monitoring.

Where we are today

In order to make improvements, we first needed to…

Pavlo Lompas

Senior Frontend Engineer @ Property Finder

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