Category: JavaScript

JavaScript React

Current state of the Concurrent Mode in React

React is constantly expanding, and with that process, there are a few cool features coming. One of them is Concurrent Mode. In this article, we go through its principles and discuss its current state. We also look at what the future might bring. The first thing to ask would be: what is the Concurrent Mode? […]

JavaScript React

Writing React forms with Formik. Validating data using Yup

Writing a React form without any additional dependencies isn’t much of a challenge itself. The same goes for applying client-side data validation. What might be troublesome is keeping all your forms consistent across a bigger project. If every developer in your team has a slightly different approach, it may turn out to be messy. With […]

Express JavaScript Node.js

TypeScript Express tutorial #12. Creating a CI/CD pipeline with Travis and Heroku

This entry is part 12 of 12 in the TypeScript Express tutorial

Once our application is up and running, we want to deploy it. In this article, we explain what Continous Integration (CI) and Continuous Delivery (CD) is. We use Travis and Heroku as an example, but the knowledge can be used with other tools also. Both Travis and Heroku can be tried out for free. Continuous […]


Measuring the quality of the User Experience with the User Timing API

The User Experience might be a bit subjective and hard to measure, but there are some parts of it that we can assess. In this article, we explore the User Timing API. With it, we can care for the performance of our applications even more. With a clear determinant of how the features that we implement […]


Improving our code with pure functions

Our code can get quite complicated. The events handlers are triggered, the HTTP calls are made. We make a lot of stuff happen that we don’t know the outcome of. The more dependencies, the more difficult it is to predict how the function might behave. In this article, we strive to make our code more […]

JavaScript Regex

Regex course – part four. Avoiding catastrophic backtracking using lookahead

This entry is part 4 of 4 in the Regex course

Regular expressions can help us solve many different problems. They can also be the source of our headaches. A recent Cloudfare outage happened due to a regular expression that caused CPU to spike to 100% on (…) machines worldwide. In this article, we go through situations we need to watch out for like the catastrophic backtracking. To help […]


Installing a Progressive Web App. Writing a Web App Manifest

The JavaScript is present in mobile apps development for quite some time now. Tools like React Native and Cordova have been around for years. Another valuable tool that we can use are Progressive Web Apps, and in this article, we go through the process of installing them. We also take a look at the current […]


Internationalization API built into your browser

There is a good chance that the application that you work on supports multiple languages. One of the things this includes is language-sensitive date handling. The most popular library that helps in achieving that is Moment.js. One of the things it handles is internationalization. Its source code contains localization for many different languages. Currently, this might not be […]