Wednesday, March 13th, 2019
Thursday, March 7th, 2019
Going Offline—the talk of the book
I gave a new talk at An Event Apart in Seattle yesterday morning. The talk was called Going Offline, which the eagle-eyed amongst you will recognise as the title of my most recent book, all about service workers.
I was quite nervous about this talk. It’s very different from my usual fare. Usually I have some big sweeping arc of history, and lots of pretentious ideas joined together into some kind of narrative arc. But this talk needed to be more straightforward and practical. I wasn’t sure how well I would manage that brief.
I knew from pretty early on that I was going to show—and explain—some code examples. Those were the parts I sweated over the most. I knew I’d be presenting to a mixed audience of designers, developers, and other web professionals. I couldn’t assume too much existing knowledge. At the same time, I didn’t want to teach anyone to such eggs.
In the end, there was an overarching meta-theme to talk, which was this: logic is more important than code. In other words, figuring out what you’re trying to accomplish (and describing it clearly) is more important than typing curly braces and semi-colons. Programming is an act of translation. Before you can translate something, you need to be able to articulate it clearly in your own language first. By emphasising that point, I hoped to make the code less overwhelming to people unfamilar with it.
I had tested the talk with some of my Clearleft colleagues, and they gave me great feedback. But I never know until I’ve actually given a talk in front of a real conference audience whether the talk is any good or not. Now that I’ve given the talk, and received more feedback, I think I can confidentally say that it’s pretty damn good.
My goal was to explain some fairly gnarly concepts—let’s face it: service workers are downright weird, and not the easiest thing to get your head around—and to leave the audience with two feelings:
- This is exciting, and
- This is something I can do today.
I deliberately left time for questions, bribing people with free copies of my book. I got some great questions, and I may incorporate some of them into future versions of this talk (conference organisers, if this sounds like the kind of talk you’d like at your event, please get in touch). Some of the points brought up in the questions were:
- Is there some kind of wizard for creating a typical service worker script for any site? I didn’t have a direct answer to this, but I have attempted to make a minimal viable service worker that could be used for just about any site. Mostly I encouraged the questioner to roll their sleeves up and try writing a bespoke script. I also mentioned the Workbox library, but I gave my opinion that if you’re going to spend the time to learn the library, you may as well spend the time to learn the underlying language.
- What are some state-of-the-art progressive web apps for offline user experiences? Ooh, this one kind of stumped me. I mean, the obvious poster children for progressive webs apps are things like Twitter, Instagram, and Pinterest. They’re all great but the offline experience is somewhat limited. To be honest, I think there’s more potential for great offline experiences by publishers. I especially love the pattern on personal sites like Una’s and Sara’s where people can choose to save articles offline to read later—like a bespoke Instapaper or Pocket. I’d love so see that pattern adopted by some big publications. I particularly like that gives so much more control directly to the end user. Instead of trying to guess what kind of offline experience they want, we give them the tools to craft their own.
- Do caches get cleaned up automatically? Great question! And the answer is mostly no—although browsers do have their own heuristics about how much space you get to play with. There’s a whole chapter in my book about being a good citizen and cleaning up your caches, but I didn’t include that in the talk because it isn’t exactly exciting: “Hey everyone! Now we’re going to do some housekeeping—yay!”
- What kind of things are in the future for service workers? Excellent question! If you think about it, a service worker is kind of a conduit that gives you access to different APIs: the Cache API and the Fetch API being the main ones now. A service worker is like an airport and the APIs are like the airlines. There are other APIs that you can access through service workers. Notifications are available now on desktop and on Android, and they’ll be coming to iOS soon. Background Sync is another powerful API accessed through service workers that will get more and more browser support over time. The great thing is that you can start using these APIs today even if they aren’t universally supported. Then, over time, more and more of your users will benefit from those enhancements.
If you attended the talk and want to learn more about about service workers, there’s my book (obvs), but I’ve also written lots of blog posts about service workers and I’ve linked to lots of resources too.
Finally, here’s a list of links to all the books, sites, and articles I referenced in my talk…
- Resilient Web Design
- The Prime Number Shitting Bear
- The Session
- Una Kravets
- Sara Soueidan
- dConstruct Archive
Progressive Web Apps
- What the heck is a “Progressive Web App”? Seriously. by Ben Halpern
- Building Progressive Web Apps by Diogo Cunha
- Before You Build a PWA You Need a SPA by Mark Muskardin
- Tweet by Jake Archibald
- What is a PWA by Salva de la Puente
- Naming Progressive Web Apps by Frances Berriman
- Progressive Web App Checklist by Google
Thursday, February 21st, 2019
A tiny lesson in query selection
We have a saying at Clearleft:
Everything is a tiny lesson.
I bet you learn something new every day, even if it’s something small. These small tips and techniques can easily get lost. They seem almost not worth sharing. But it’s the small stuff that takes the least effort to share, and often provides the most reward for someone else out there. Take for example, this great tip for getting assets out of Sketch that Cassie shared with me.
querySelector to get a reference to an element in the DOM:
var someElement = document.querySelector('.someClass');
Before going any further, check to make sure that the reference isn’t falsey (in other words, make sure that DOM node actually exists):
if (!someElement) return;
That will exit the script if there’s no element with a class of
someClass on the page.
The situation that tripped us up was like this:
var myLinks = document.querySelectorAll('a.someClass'); if (!myLinks) return;
That should exit the script if there are no
A elements with a class of
As it turns out,
querySelectorAll is subtly different to
querySelector. If you give
querySelector a reference to non-existent element, it will return a value of
null (I think). But
querySelectorAll always returns an array (well, technically it’s a NodeList but same difference mostly). So if the selector you pass to
querySelectorAll doesn’t match anything, it still returns an array, but the array is empty. That means instead of just testing for its existence, you need to test that it’s not empty by checking its
if (!myLinks.length) return;
That’s a tiny lesson.
Wednesday, January 30th, 2019
Saturday, January 19th, 2019
Tuesday, January 1st, 2019
These are good challenges to think about. Almost all of them are user-focused, and there’s a refreshing focus away from reaching for a library:
It’s tempting to read about these problems with a particular view library or a data fetching library in mind as a solution. But I encourage you to pretend that these libraries don’t exist, and read again from that perspective. How would you approach solving these issues?
Tuesday, December 18th, 2018
It’s a terribly clickbaity (and negatively phrased) title, but if you turn it around, there’s some good advcie in here for deciding where to focus when it comes to dev technology:
- Programming languages are different, but design smells are alike.
- Frameworks are different, but the same design patterns shine through.
- Developers are different, but rules of dealing with people are uniform.
Wednesday, December 5th, 2018
A five-part video series from Ire on how she built the “save for offline” functionality on her site.
The first one is about getting a set set up on Ghost so you can probably safely skip that one and go straight to the second video to get down to the nitty-gritty of the Cache API and service workers.
Monday, December 3rd, 2018
Absolutely spot on! And it cuts both ways:
Saturday, November 17th, 2018
Monday, October 29th, 2018
There’s a theory that you can cure this by following standards, except there are more “standards” than there are things computers can actually do, and these standards are all variously improved and maligned by the personal preferences of the people coding them, so no collection of code has ever made it into the real world without doing a few dozen identical things a few dozen not even remotely similar ways. The first few weeks of any job are just figuring out how a program works even if you’re familiar with every single language, framework, and standard that’s involved, because standards are unicorns.
Monday, October 22nd, 2018
Thursday, October 11th, 2018
Some sensible answers to this question here…
…of which, exactly zero mention end users.
Monday, October 8th, 2018
The fascinating results of Brad’s survey.
Personally, I’m not a fan of nesting. I feel it obfuscates more than helps. And it makes searching for a specific selector tricky.
That said, Danielle feels quite strongly that nesting is the way to go, so on Clearleft projects, that’s how we write Sass + BEM.
Maintaining an open source project is a rollercoaster ride with high peaks and very low troughs.
Release frequency is down. Questions increasingly go unanswered. Issues remain in a triage, unresolved state. Uncertainty and frustration brew within the community room.
Brian’s experience with Pattern Lab very much mirrors Mark’s experience with Fractal. The pressure. The stress. But there’s also the community.
A maintainer must keep the needs of their project, their community, and their own needs in constant harmony.
This is hard!
Wednesday, August 8th, 2018
I started writing for myself. The writing was helpful for me and luckily it was helpful for other people as well. But even if you’re the only one that reads your blog it is still helpful as a way to learn.
Thursday, August 2nd, 2018
Chris has written about switching code editors. I’m a real stick-in-the-mud when it comes to switching editors. Partly that’s because I’m generally pretty happy with whatever I’m using (right now it’s Atom) but it’s also because I just don’t get that excited about software like this. I probably should care more; I spend plenty of time inside a code editor. And I should really take the time to get to grips with features like keyboard shortcuts—I’m sure I’m working very inefficiently. But, like I said, I find it hard to care enough, and on the whole, I’m content.
I was struck by this observation from Chris:
When moving, I have to take time to make sure it works pretty much like the old one.
That reminded me of a recent switch I made, not with code editors, but with browsers.
I’ve been using Chrome for years. One day it started crashing a lot. So I decided to make the switch to Firefox. Looking back, I’m glad to have had this prompt—I think it’s good to shake things up every now and then, so I don’t get too complacent (says the hypocrite who can’t be bothered to try a new code editor).
Just as Chris noticed with code editors, it was really important that I could move bookmarks (and bookmarklets!) over to my new browser. On the whole, it went pretty smoothly. I had to seek out a few browser extensions but that was pretty much it. And because I use a password manager, logging into all my usual services wasn’t a hassle.
Of all the pieces of software on my computer, the web browser is the one where I definitely spend the most time: reading, linking, publishing. At this point, I’m very used to life with Firefox as my main browser. It’s speedy and stable, and the dev tools are very similar to Chrome’s.
Maybe I’ll switch to Safari at some point. Like I said, I think it’s good to shake things up and get out of my comfort zone.
Now, if I really wanted to get out of my comfort zone, I’d switch operating systems like Dave did with his move to Windows. And I should really try using a different phone OS. Again, this is something that Dave tried with his switch to Android (although that turned out to be unacceptably creepy), and Paul did it ages ago using a Windows phone for a week.
There’s probably a balance to be struck here. I think it’s good to change code editors, browsers, even operating systems and phones every now and then, but I don’t want to feel like I’m constantly in learning mode. There’s something to be said for using tools that are comfortable and familiar, even if they’re outdated.
Thursday, July 19th, 2018
(Caveat: because everything’s happening in
script elements in the browser, what’s outlined here will only do client-side rendering.)
Thursday, July 12th, 2018
I’ve thought often of how our design and prototyping tools for the web are often not of the web. Tools like Photoshop and Sketch and Invision create approximations but need to walk the line between being a tool to build native apps and to build web apps. They do well in their ability to quickly validate designs but do little to validate technical approach.
Wednesday, July 4th, 2018
This is a lovely review of Going Offline from Garrett:
With his typical self-effacing humour (chapter titles include Making Fetch Happen and Cache Me If You Can), and easy manner, Jeremy explains how Service Workers, uh, work, the clever things you can do with them, and most importantly, how to build your own.
Best of all, he’s put it into action!
To that end, this site now has its own home-grown, organic, corn fed, Service Worker.