Delivering WordPress in 7KB

Over the past six months, I've become increasingly interested in the topic of web sustainability. The carbon footprint of the Internet was not something I used to give much thought to, which is surprising considering my interest in environmental issues and the fact that my profession is web-based.


The web can be anything we want it to be

I really enjoyed this chat between Bruce Lawson and Mustafa Kurtuldu where they talked about browser support and the health of the web. Bruce expands upon a lot of the thoughts in a post he wrote last year called World Wide Web, Not Wealthy Western Web where he writes:

...across the world, regardless of disposable income, regardless of hardware or network speed, people want to consume the same kinds of goods and services. And if your websites are made for the whole world, not just the wealthy Western world, then the next 4 billion people might consume the stuff that your organization makes.


Hey hey `font-display`

Y'all know about font-display? It's pretty great. It's a CSS property that you can use within @font-face blocks to control how, visually, that font loads. Font loading is really pretty damn complicated. Here's a guide from Zach Leatherman to prove it, which includes over 10 font loading strategies, including strategies that involve critical inline CSS of subsets of fonts combined with loading the rest of the fonts later through JavaScript. It ain't no walk in the park.


Chrome DevTools “Local Overrides”

There's been two really interesting videos released recently that use the "Local Overrides" feature of Chrome DevTools in order to play with web performance without even touching the original source code.

The big idea is that you can literally edit CSS and reload the page and your changes stick. Meaning you can use the other performance testing tools inside DevTools to see if your changes had the effect you wanted them to have. Great for showing a client a change without them having to set up a whole dev environment for you.

Three Techniques for Performant Custom Font Usage

There’s a lot of good news in the world of web fonts!

  1. The forthcoming version of Microsoft Edge will finally implement unicode-range, the last modern browser to do so.
  2. Preload and font-display are landing in Safari and Firefox.
  3. Variable fonts are shipping everywhere.

Using custom fonts in a performant way is becoming far easier. Let’s take a peek at some things we can do when using custom fonts to make sure we’re being as performant as we can be.


Third-Party Scripts

Trent Walton:

My latest realization is that delivering a performant, accessible, responsive, scalable website isn’t enough: I also need to consider the impact of third-party scripts. No matter how solid I think my prototype is, it doesn’t absolve me from paying attention to what happens during implementation, specifically when it comes to the addition of these third-party scripts.

I recently had a conversation with a friend working on quite a high profile e-commerce site. They were hired to develop the site, but particularly with performance in mind. They were going the PWA route, but were immediately hamstrung by third-party scripts. One of them, apparently unavoidably, couldn't be HTTPS, meaning the site was immediately disqualified from being a PWA. They could still do a good job in many other areas, but right and left their great performance work was slaughtered by third-party scripts. I don't envy being in that position.


Monitoring unused CSS by unleashing the raw power of the DevTools Protocol

From Johnny's dev blog:

The challenge: Calculate the real percentage of unused CSS

Our goal is to create a script that will measure the percentage of unused CSS of this page. Notice that the user can interact with the page and navigate using the different tabs.

DevTools can be used to measure the amount of unused CSS in the page using the Coverage tab. Notice that the percentage of unused CSS after the page loads is ~55%, but after clicking on each of the tabs, more CSS rules are applied and the percentage drops down to just ~15%.

That's why I'm so skeptical of anything that attempts to measure "unused CSS." This is an incredibly simple demo (all it does is click some tabs) and the amount of unused CSS changes dramatically.


Front-End Performance Checklist

Vitaly Friedman swings wide with a massive list of performance considerations. It's a well-considered mix of old tactics (cutting the mustard, progressive enhancement, etc.) and newer considerations (tree shaking, prefetching, etc.). I like the inclusion of a quick wins section since so much can be done for little effort; it's important to do those things before getting buried in more difficult performance tasks.

Speaking of considering performance, Philip Walton recently dug into what interactive actually means, in a world where we throw around acronyms like TTI:

But what exactly does the term “interactivity” mean?

I think most people reading this article probably know what the word “interactivity” means in general. The problem is, in recent years the word has been given a technical meaning (e.g. in the metric “Time to Interactive” or TTI), and unfortunately the specifics of that meaning are rarely explained.

One reason is that the page depends on JavaScript and that JavaScript hasn't downloaded, parsed, and run yet. That reason is well-trod, but there is another one: the "main thread" might be busy doing other stuff. That is a particularly insidious enemy of performance, so definitely read Philip's article to understand more about that.

Also, if you're into front-end checklists, check out David Dias' Front-End Checklist.

Breaking Down the Performance API

JavaScript’s Performance API is prudent, because it hands over tools to accurately measure the performance of Web pages, which, in spite of being performed since long before, never really became easy or precise enough.

That said, it isn’t as easy to get started with the API as it is to actually use it. Although I’ve seen extensions of it covered here and there in other posts, the big picture that ties everything together is hard to find.