Josh W Comeau homepage

Of all the latest and greatest CSS features, the “:has” pseudo-class wasn’t exactly at the top of my wishlist. Once I started using it, however, I kept discovering incredible things I could do with it. It’s now become a core part of my toolkit! In this blog post, I'll show you some practical real-world problems I solved using “:has”, as well as some wild experiments that blew my mind!

The “Promises” API is a surprisingly tricky part of modern JavaScript. Without the right context, it doesn’t make much sense at all! In this tutorial, you’ll build an intuition for how Promises work by getting a deeper understanding of JavaScript and its limitations.

useDeferredValue is one of the most underrated React hooks. It allows us to dramatically improve the performance of our applications in certain contexts. I recently used it to solve a gnarly performance problem on this blog, and in this tutorial, I'll show you how! ⚡

Understanding the future of CSS-in-JS and React

You can’t make an omelette without cracking a few eggs, and when the core React team unveiled their vision for the future of React, some of my favourite libraries got scrambled 😅. In this blog post, we’re going to explore the compatibility issues between React Server Components and CSS-in-JS libraries like styled-components. You’ll understand what the issue is, what the options are, and what’s on the horizon.

The Ultimate Guide to Centering in CSS

Back in the day, centering an element was one of the trickiest things in CSS. As the language has evolved, we’ve been given lots of new tools we can use… But how do we pick the best option? When do we use Flexbox, or CSS Grid, or something else? Let's dig into it.

CSS Grid is an incredibly powerful tool for building layouts on the web, but like all powerful tools, there's a significant learning curve. In this tutorial, we'll build a mental model for how CSS Grid works and how we can use it effectively. I'll share the biggest 💡 lightbulb moments I've had in my own learning journey.

One of the most commonly-misunderstood operators is Modulo (%). In this tutorial, we'll unpack exactly what this little bugger does, and learn how it can help us solve practical problems.

This year, the React team unveiled something they've been quietly researching for years: an official way to run React components exclusively on the server. This is a significant paradigm shift, and it's caused a whole lot of confusion in the React community. In this tutorial, we'll explore this new world, and build an intuition for how it works, and how we can take advantage of it.

Happy Pride month! In this tutorial, I'll share a handful of my favourite animation tricks. You'll learn how to build an animated wavy pride flag using CSS keyframes and linear gradients. We'll also see how to make it dynamic using React. 🏳️‍🌈

Exploring the difference between assignment and mutation in JavaScript

The “const” keyword in JavaScript is used to create constants, variables that can't change. Curiously, though, we do seem to be able to edit objects and arrays that are created using “const”. In this tutorial, we're going to dig into the incredibly-important distinction between “assignment” and “mutation” in JavaScript.

Large language models like GPT-4 are becoming increasingly capable, at an alarming rate. Within a couple of years, we won't need developers any more! …Or at least, that's the narrative going viral on Twitter. I'm much more optimistic about what these AI advancements mean for the future of software development.

Pitfalls, gotchas, and footguns, oh my!

I used to teach React at a local coding bootcamp, and I noticed that students kept getting tripped up by the same handful of things. In this article, we're going to go through 9 of the most dastardly gotchas. I'll show you how to solve these common problems, so you can avoid a lot of potential frustration!