Tags: development



Friday, May 26th, 2017

traintimes.org.uk performance notes

I love, love, *love, traintimes.org.uk—partly because it’s so useful, but also because it’s so fast. I know public transport is the clichéd use-case when it comes to talking about web performance, but in this case it’s genuine: I use the site on trains and in airports.

Matthew gives a blow-by-blow account of the performance optimisations he’s made for the site, including a service worker. The whole thing is a masterclass in performance and progressive enhancement. I’m so glad he took the time to share this!

Wednesday, May 24th, 2017

A workshop on evaluating technology

After hacking away at Indie Web Camp Düsseldorf, I stuck around for Beyond Tellerrand. I ended up giving a talk, stepping in for Ellen. I was a poor substitute, but I hope I entertained the lovely audience for 45 minutes.

After Beyond Tellerrand, I got on a train to Nuremberg …along with a dozen of my peers who were also at the event.

All aboard the Indie Web Train from Düsseldorf to Nürnberg. Indie Web Train.

I arrived right in the middle of Web Week Nürnberg. Among the many events going on was a workshop that Joschi arranged for me to run called Evaluating Technology. The workshop version of my Beyond Tellerrand talk, basically.

This was an evolution of a workshop I ran a while back. I have to admit, I was a bit nervous going into this. I had no tangible material prepared; no slides, no handouts, nothing. Instead the workshop is a collaborative affair. In order for it to work, the attendees needed to jump in and co-create it with me. Luckily for me, I had a fantastic and enthusiastic group of people at my workshop.

Evaluating Technology

We began with a complete braindump. “Name some tools and technologies,” I said. “Just shout ‘em out.” Shout ‘em out, they did. I struggled to keep up just writing down everything they said. This was great!

Evaluating Technology

The next step was supposed to be dot-voting on which technologies to cover, but there were so many of them, we introduced an intermediate step: grouping the technologies together.

Evaluating Technology Evaluating Technology

Once the technologies were grouped into categories like build tools, browser APIs, methodologies etc., we voted on which categories to cover, only then diving deeper into specific technologies.

I proposed a number of questions to ask of each technology we covered. First of all, who benefits from the technology? Is it a tool for designers and developers, or is it a tool for the end user? Build tools, task runners, version control systems, text editors, transpilers, and pattern libraries all fall into the first category—they make life easier for the people making websites. Browser features generally fall into the second category—they improve the experience for the end user.

Looking at user-facing technologies, we asked: how well do they fail? In other words, can you add this technology as an extra layer of enhancement on top of what you’re building or do you have to make it a foundational layer that’s potentially a single point of failure?

For both classes of technologies, we asked the question: what are the assumptions? What fundamental philosophy has been baked into the technology?

Evaluating Technology Evaluating Technology

Now, the point of this workshop is not for me to answer those questions. I have a limited range of experience with the huge amount of web technologies out there. But collectively all of us attending the workshop will have a good range of experience and knowledge.

Interesting then that the technologies people voted for were:

  • service workers,
  • progressive web apps,
  • AMP,
  • web components,
  • pattern libraries and design systems.

Those are topics I actually do have some experience with. Lots of the attendees had heard of these things, they were really interested in finding out more about them, but they hadn’t necessarily used them yet.

And so I ended up doing a lot of the talking …which wasn’t the plan at all! That was just the way things worked out. I was more than happy to share my opinions on those topics, but it was of a shame that I ended up monopolising the discussion. I felt for everyone having to listen to me ramble on.

Still, by the end of the day we had covered quite a few topics. Better yet, we had a good framework for categorising and evaluating web technologies. The specific technologies we covered were interesting enough, but the general approach provided the lasting value.

All in all, a great day with a great group of people.

Evaluating Technology

I’m already looking forward to running this workshop again. If you think it would be valuable for your company, get in touch.

Tuesday, May 23rd, 2017

Going offline at Indie Web Camp Düsseldorf

I’ve just come back from a ten-day trip to Germany. The trip kicked off with Indie Web Camp Düsseldorf over the course of a weekend.

IndieWebCamp Düsseldorf 2017

Once again the wonderful people at Sipgate hosted us in their beautiful building, and once again myself and Aaron helped facilitate the two days.

IndieWebCamp Düsseldorf 2017

Saturday was the BarCamp-like discussion day. Plenty of interesting topics were covered. I led a session on service workers, and that’s also what I decided to work on for the second day—that’s when the talking is done and we get down to making.

IndieWebCamp Düsseldorf 2017 IndieWebCamp Düsseldorf 2017 IndieWebCamp Düsseldorf 2017 IndieWebCamp Düsseldorf 2017

I like what Ethan is doing on his offline page. He shows a list of pages that have been cached, but instead of just listing URLs, he shows a title and description for each page.

I’ve already got a separate cache for pages that gets added to as the user browses around my site. I needed to figure out a way to store the metadata for those pages so that I could then display it on the offline page. I came up with a workable solution, and interestingly, it involved no changes to the service worker script at all.

When you visit any blog post, I put metadata about the page into localStorage (after first checking that there’s an active service worker):

if (navigator.serviceWorker && navigator.serviceWorker.controller) {
  window.addEventListener('load', function() {
    var data = {
      "title": "A minority report on artificial intelligence",
      "description": "Revisiting Spielberg’s films after a decade and a half.",
      "published": "May 7th, 2017",
      "timestamp": "1494171049"

In my case, I’m outputting the metadata from the server, but you could just as easily grab some from the DOM like this:

var data = {
  "title": document.querySelector("title").innerText,
  "description": document.querySelector("meta[name='description']").getAttribute("contents")

Meanwhile in my service worker, when you visit that same page, it gets added to a cache called “pages”. Both localStorage and the cache API are using URLs as keys. I take advantage of that on my offline page.

The nice thing about writing JavaScript on my offline page is that I know the page will only be seen by modern browsers that support service workers, so I can use all sorts of fancy from ES6, or whatever we’re calling it now.

I start by looping through the keys of the “pages” cache (that’s right—the cache API isn’t just for service workers; you can access it from any script). Then I check to see if there is a corresponding localStorage key with the same string (a URL). If there is, I pull the metadata out of local storage and add it to an array called browsingHistory:

const browsingHistory = [];
.then( cache => {
  .then(keys => {
    keys.forEach( request => {
      let data = JSON.parse(localStorage.getItem(request.url));
        if (data) {
          data['url'] = request.url;

Then I sort the list of pages in reverse chronological order:

browsingHistory.sort( (a,b) => {
  return b.timestamp - a.timestamp;

Now I loop through each page in the browsing history list and construct a link to each URL, complete with title and description:

let markup = '';
browsingHistory.forEach( data => {
  markup += `
<h2><a href="${ data.url }">${ data.title }</a></h2>
<p>${ data.description }</p>
<p class="meta">${ data.published }</p>

Finally I dump the constructed markup into a waiting div in the page with an ID of “history”:

let container = document.getElementById('history');
container.insertAdjacentHTML('beforeend', markup);

All those steps need to be wrapped inside the then clause attached to caches.open("pages") because the cache API is asynchronous.

There you have it. Now if you’re browsing adactio.com and your network connection drops (or my server goes offline), you can choose from a list of pages you’ve previously visited.

The current situation isn’t ideal though. I’ve got a clean-up operation in my service worker to limit the number of items stored in my “pages” cache. The cache never gets bigger than 35 items. But there’s no corresponding clean-up of metadata stored in localStorage. So there could be a lot more bits of metadata in local storage than there are pages in the cache. It’s not harmful, but it’s a bit wasteful.

I can’t do a clean-up of localStorage from my service worker because service workers can’t access localStorage. There’s a very good reason for that: the localStorage API is synchronous, and everything that happens in a service worker needs to be asynchronous.

Service workers can access indexedDB: it’s asynchronous. I could use indexedDB instead of localStorage, but I’m not a masochist. My best bet would be to use the localForage library, which wraps indexedDB in the simple syntax of localStorage.

Maybe I’ll do that at the next Homebrew Website Club here in Brighton.

Learn CSS Grid - A Guide to Learning CSS Grid | Jonathan Suh

A quick visual guide to CSS Grid properties and values.

Service Worker Security FAQ - The Chromium Projects

Got questions about the security of service workers? This document probably has the answer.

Evaluating Technology – Jeremy Keith – btconfDUS2017 on Vimeo

I wasn’t supposed to speak at this year’s Beyond Tellerrand conference, but alas, Ellen wasn’t able to make it so I stepped in and gave my talk on evaluating technology.

Monday, May 22nd, 2017

Are we making the web too complicated? | Seldo.Com Blog

Laurie Voss on the trade-off between new powerful web dev tools, and the messiness that abusing those tools can bring:

Is modern web development fearsomely, intimidatingly complicated? Yes, and that’s a problem. Will we make it simpler? Definitely, but probably not as soon as you’d like. Is all this new complexity worthwhile? Absolutely.

I agree that there’s bound to be inappropriate use of technologies, but I don’t agree that we should just accept it:

Are there some people using a huge pile of JavaScript and a monstrous build chain to throw together a single-pager web site with one box that collects an email address? For sure. And that’s silly and unnecessary. But so what? The misuse of technology does not invalidate it.

I think we can raise our standards. Inappropriate use of technology might have been forgivable ten years ago, but if we want web development to be taken seriously as a discipline, I think we should endeavour to use our tools and technologies appropriately.

But we can all agree that the web is a wonderful thing:

Nobody but nobody loves the web more than I do. It’s my baby. And like a child, it’s frustrating to watch it struggle and make mistakes. But it’s amazing to watch it grow up.

Friday, May 19th, 2017

Presentation: Accessibility in a Responsive World, A11Y Days 2017

There are some great hands-on accessibility patterns in this talk transcript from Scott.

Thursday, May 18th, 2017

Style Guide Guide | Style Guide Guide

If you want to understand the thinking behind this style guide guide, be sure to read Brad’s style guide guide guide.

Mavo: A new, approachable way to create Web applications

A really interesting new project from Lea that aims to put dynamic sites within the reach of everyone. The emphasis is on declarative languages—HTML and CSS—no JavaScript knowledge required.

Lea has also written an introductory article on Smashing Mag.

Why Fast Matters // Speaker Deck

Slides from Harry’s recent talk on performance.

Sunday, May 14th, 2017

ngrok - secure introspectable tunnels to localhost

This looks like a useful tool, not just for testing locally-hosted sites (say, at a device lab), but also for making locally-hosted sites run on HTTPS so you can test service workers.

Friday, May 5th, 2017

Patterns Day speakers

Ticket sales for Patterns Day are going quite, quite briskly. If you’d like to come along, but you don’t yet have a ticket, you might want to remedy that. Especially when you hear about who else is going to be speaking…

Sareh Heidari works at the BBC building websites for a global audience, in as many as twenty different languages. If you want to know about strategies for using CSS at scale, you definitely want to hear this talk. She just stepped off stage at the excellent CSSconf EU in Berlin, and I’m so happy that Sareh’s coming to Brighton!

Patterns Day isn’t the first conference about design systems and pattern libraries on the web. That honour goes to the Clarity conference, organised by the brilliant Jina Anne. I was gutted I couldn’t make it to Clarity last year. By all accounts, it was excellent. When I started to form the vague idea of putting on an event here in the UK, I immediately contacted Jina to make sure she was okay with it—I didn’t want to step on her toes. Not only was she okay with it, but she really wanted to come along to attend. Well, never mind attending, I said, how about speaking?

I couldn’t be happier that Jina agreed to speak. She has had such a huge impact on the world of pattern libraries through her work with the Lightning design system, Clarity, and the Design Systems Slack channel.

The line-up is now complete. Looking at the speakers, I find myself grinning from ear to ear—it’s going to be an honour to introduce each and every one of them.

This is going to be such an excellent day of fun and knowledge. I can’t wait for June 30th!

Thursday, May 4th, 2017

Going offline. — Ethan Marcotte

Ethan has added a service worker to his site and he’s got a nifty little recipe for showing a list of saved-for-offline articles.

Tuesday, May 2nd, 2017

Styling the Patterns Day site

Once I had a design direction for the Patterns Day site, I started combining my marked-up content with some CSS. Ironically for an event that’s all about maintainability and reusability, I wrote the styles for this one-page site with no mind for future use. I treated the page as a one-shot document. I even used ID selectors—gasp! (the IDs were in the HTML anyway as fragment identifiers).

The truth is I didn’t have much of a plan. I just started hacking away in a style element in the head of the document, playing around with colour, typography, and layout.

I started with the small-screen styles. That wasn’t a conscious decision so much as just the way I do things automatically now. When it came time to add some layout for wider viewports, I used a sprinkling of old-fashioned display: inline-block so that things looked so-so. I knew I wanted to play around with Grid layout so the inline-block styles were there as fallback for non-supporting browsers. Once things looked good enough, the fun really started.

I was building the site while I was in Seattle for An Event Apart. CSS Grid layout was definitely a hot topic there. Best of all, I was surrounded by experts: Jen, Rachel, and Eric. It was the perfect environment for me to dip my toes into the waters of grid.

Jen was very patient in talking me through the concepts, syntax, and tools for using CSS grids. Top tip: open Firefox’s inspector, select the element with the display:grid declaration, and click the “waffle” icon—instant grid overlay!

For the header of the Patterns Day site, I started by using named areas. That’s the ASCII-art approach. I got my head around it and it worked okay, but it didn’t give me quite the precision I wanted. I switched over to using explicit grid-row and grid-column declarations.

It’s definitely a new way of thinking about layout: first you define the grid, then you place the items on it (rather than previous CSS layout systems where each element interacted with the elements before and after). It was fun to move things around and not have to worry about the source order of the elements …as long as they were direct children of the element with display:grid applied.

Without any support for sub-grids, I ended up having to nest two separate grids within one another. The logo is a grid parent, which is inside the header, also a grid parent. I managed to get things to line up okay, but I think this might be a good use case for sub-grids.

The logo grid threw up some interesting challenges. I wanted each letter of the words “Patterns Day” to be styleable, but CSS doesn’t give us any way to target individual letters other than :first-letter. I wrapped each letter in a b element, made sure that they were all wrapped in an element with an aria-hidden attribute (so that the letters wouldn’t be spelled out), and then wrapped that in an element with an aria-label of “Patterns Day.” Now I could target those b elements.

For a while, I also had a br element (between “Patterns” and “Day”). That created some interesting side effects. If a br element becomes a grid item, it starts to behave very oddly: you can apply certain styles but not others. Jen and Eric then started to test other interesting elements, like hr. There was much funkiness and gnashing of specs.

It was a total nerdfest, and I loved every minute of it. This is definitely the most excitement I’ve felt around CSS for a while. It feels like a renaissance of zen gardens and layout reservoirs (kids, ask your parents).

After a couple of days playing around with grid, I had the Patterns Day site looking decent enough to launch. I dabbled with some other fun CSS stuff in there too, like gratuitous clip paths and filters when hovering over the speaker images, and applying shape-outside with an image mask.

Go ahead and view source on the Patterns Day page if you want—I ended up keeping all the CSS in the head of the document. That turned out to be pretty good for performance …for first-time visits anyway. But after launching the site, I couldn’t resist applying some more performance tweaks.

Monday, May 1st, 2017

Offline Web Applications | Udacity

This is a free online video course recorded by Jake a couple of years back. It’s got a really good step-by-step introduction to service workers, delivered in Jake’s typically witty way. Some of the details are a bit out of date, and I must admit that I bailed when it got to IndexedDB, but I highly recommend giving this a go.

There’s also a free course on web accessibility I’m planning to check out.

Springer Nature frontend playbook: house style guide

I like it when organisations share their in-house coding styles. This one from Springer Nature not only has guides for HTML, CSS, and JavaScript, but it also has a good primer on progressive enhancement.

Sunday, April 30th, 2017

Sessions by Pusher

Oodles and oodles of videos of talks from London developer meetups.

Friday, April 28th, 2017

A Case for Progressive Web Applications in 2017

If your company is or is planning on doing business in emerging markets, architecting your web applications for performance through progressive enhancements is one easy way to drastically improve accessibility, retention, and user experience.

This article uses “progressive enhancement” and “progressive web app” interchangeably, which would be true in an ideal world. This is the first of a three part series, and it sounds like it will indeed document how to take an existing site and enhance it into a progressive web app—a strategy I much prefer to creating a separate silo that only works for a subset of devices (the app-shell model being pushed by Google).

Introducing Fractal and Federalist | U.S. Web Design Standards

Another instance of Fractal in the wild, this time for the Federalist design system.

Why Fractal?

  • It’s open source.
  • It’s easy to use.
  • It generates standalone HTML previews of each component.
  • It uses or supports many of the technologies we use already.
  • Fractal offers a customizable theme engine.