Journal

2509 sparkline

Tuesday, August 7th, 2018

Console methods

Whenever I create a fetch event inside a service worker, my code roughly follows the same pattern. There’s a then clause which gets executed if the fetch is successful, and a catch clause in case anything goes wrong:

fetch( request)
.then( fetchResponse => {
    // Yay! It worked.
})
.catch( fetchError => {
    // Boo! It failed.
});

In my book—Going Offline—I’m at pains to point out that those arguments being passed into each clause are yours to name. In this example I’ve called them fetchResponse and fetchError but you can call them anything you want.

I always do something with the fetchResponse inside the then clause—either I want to return the response or put it in a cache.

But I rarely do anything with fetchError. Because of that, I’ve sometimes made the mistake of leaving it out completely:

fetch( request)
.then( fetchResponse => {
    // Yay! It worked.
})
.catch( () => {
    // Boo! It failed.
});

Don’t do that. I think there’s some talk of making the error argument optional, but for now, some browsers will get upset if it’s not there.

So always include that argument, whether you call it fetchError or anything else. And seeing as it’s an error, this might be a legitimate case for outputing it to the browser’s console, even in production code.

And yes, you can output to the console from a service worker. Even though a service worker can’t access anything relating to the document object, you can still make use of window.console, known to its friends as console for short.

My muscle memory when it comes to sending something to the console is to use console.log:

fetch( request)
.then( fetchResponse => {
    return fetchResponse;
})
.catch( fetchError => {
    console.log(fetchError);
});

But in this case, the console.error method is more appropriate:

fetch( request)
.then( fetchResponse => {
    return fetchResponse;
})
.catch( fetchError => {
    console.error(fetchError);
});

Now when there’s a connectivity problem, anyone with a console window open will see the error displayed bold and red.

If that seems a bit strident to you, there’s always console.warn which will still make the output stand out, but without being quite so alarmist:

fetch( request)
.then( fetchResponse => {
    return fetchResponse;
})
.catch( fetchError => {
    console.warn(fetchError);
});

That said, in this case, console.error feels like the right choice. After all, it is technically an error.

Friday, August 3rd, 2018

Greater expectations

I got an intriguing email recently from someone who’s a member of The Session, the community website about Irish traditional music that I run. They said:

When I recently joined, I used my tablet to join. Somewhere I was able to download The Session app onto my tablet.

But there is no native app for The Session. Although, as it’s a site that I built, it is, a of course, progressive web app.

They went on to say:

I wanted to put the app on my phone but I can’t find the app to download it. Can I have the app on more than one device? If so, where is it available?

I replied saying that yes, you can absolutely have it on more than one device:

But you don’t find The Session app in the app store. Instead you go to the website https://thesession.org and then add it to your home screen from your browser.

My guess is that this person had added The Session to the home screen of their Android tablet, probably following the “add to home screen” prompt. I recently added some code to use the window.beforeinstallprompt event so that the “add to home screen” prompt would only be shown to visitors who sign up or log in to The Session—a good indicator of engagement, I reckon, and it should reduce the chance of the prompt being dismissed out of hand.

So this person added The Session to their home screen—probably as a result of being prompted—and then used it just like any other app. At some point, they didn’t even remember how the app got installed:

Success! I did it. Thanks. My problem was I was looking for an app to download.

On the one hand, this is kind of great: here’s an example where, in the user’s mind, there’s literally no difference between the experience of using a progressive web app and using a native app. Win!

But on the other hand, the expectation is still that apps are to be found in an app store, not on the web. This expectation is something I wrote about recently (and Justin wrote a response to that post). I finished by saying:

Perhaps the inertia we think we’re battling against isn’t such a problem as long as we give people a fast, reliable, engaging experience.

When this member of The Session said “My problem was I was looking for an app to download”, I responded by saying:

Well, I take that as a compliment—the fact that once the site is added to your home screen, it feels just like a native app. :-)

And they said:

Yes, it does!

Thursday, August 2nd, 2018

Switching

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.

Wednesday, July 25th, 2018

The history of design systems at Clearleft

Danielle has posted a brief update on Fractal:

We decided to ask the Fractal community for help, and the response has been overwhelming. We’ve received so many offers of support in all forms that we can safely say that development will be starting up again shortly.

It’s so gratifying to see that other people are finding Fractal to be as useful to them as it is to us. We very much appreciate all their support!

Although Fractal itself is barely two years old, it’s part of a much longer legacy at Clearleft

It all started with Natalie. She gave a presentation back in 2009 called Practical Maintainable CSS . She talks about something called a pattern porfolio—a deliverable that expresses every component and documents how the markup and CSS should be used.

When Anna was interning at Clearleft, she was paired up with Natalie so she was being exposed to these ideas. She then expanded on them, talking about Front-end Style Guides. She literally wrote the book on the topic, and starting curating the fantastic collection of examples at styleguides.io.

When Paul joined Clearleft, it was a perfect fit. He was already obsessed with style guides (like the BBC’s Global Experience Language) and started writing and talking about styleguides for the web:

At Clearleft, rather than deliver an inflexible set of static pages, we present our code as a series of modular components (a ‘pattern portfolio’) that can be assembled into different configurations and page layouts as required.

Such systematic thinking was instigated by Natalie, yet this is something we continually iterate upon.

To see the evolution of Paul’s thinking, you can read his three part series from last year on designing systems:

  1. Theory, Practice, and the Unfortunate In-between,
  2. Layers of Longevity, and
  3. Components and Composition

Later, Charlotte joined Clearleft as a junior developer, and up until that point, hadn’t been exposed to the idea of pattern libraries or design systems. But it soon became clear that she had found her calling. She wrote a brilliant article for A List Apart called From Pages to Patterns: An Exercise for Everyone and she started speaking about design systems at conferences like Beyond Tellerrand. Here, she acknowledges the changing terminology over the years:

Pattern portfolio is a term used by Natalie Downe when she started using the technique at Clearleft back in 2009.

Front-end style guides is another term I’ve heard a lot.

Personally, I don’t think it matters what you call your system as long as it’s appropriate to the project and everyone uses it. Today I’m going to use the term “pattern library”.

(Mark was always a fan of the term “component library”.)

Now Charlotte is a product manager at Ansarada in Sydney and the product she manages is …the design system!

Thinking back to my work on starting design systems, I didn’t realise straight away that I was working on a product. Yet, the questions we ask are similar to those we ask of any product when we start out. We make decisions on things like: design, architecture, tooling, user experience, code, releases, consumption, communication, and more.

It’s been fascinating to watch the evolution of design systems at Clearleft, accompanied by an evolution in language: pattern portfolios; front-end style guides; pattern libraries; design systems.

There’s been a corresponding evolution in prioritisation. Where Natalie was using pattern portfolios as a deliverable for handover, Danielle is now involved in the integration of design systems within a client’s team. The focus on efficiency and consistency that Natalie began is now expressed in terms of design ops—creating living systems that everyone is involved in.

When I step back and look at the history of design systems on the web, there are some obvious names that have really driven their evolution and adoption, like Jina Anne, Brad Frost, and Alla Kholmatova. But I’m amazed at the amount of people who have been through Clearleft’s doors that have contributed so, so much to this field:

Natalie Downe, Anna Debenham, Paul Lloyd, Mark Perkins, Charlotte Jackson, and Danielle Huntrods …thank you all!

Tuesday, July 24th, 2018

Altering expectations

Luke has written up the selection process he went through when Clearleft was designing the Virgin Holidays app. When it comes to deploying on mobile, there were three options:

  1. Native apps
  2. A progressive web app
  3. A hybrid app

The Virgin Holidays team went with that third option.

Now, it will come as no surprise that I’m a big fan of the second option: building a progressive web app (or turning an existing site into a progressive web app). I think a progressive web app is a great solution for travel apps, and the use-case that Luke describes sounds perfect:

Easy access to resort staff and holiday details that could be viewed offline to help as many customers as possible travel without stress and enjoy a fantastic holiday

Luke explains why they choice not to go with a progressive web app.

The current level of support and leap in understanding meant we’d risk alienating many of our customers.

The issue of support is one that is largely fixed at this point. When Clearleft was working on the Virgin Holidays app, service workers hadn’t landed in iOS. Hence, the risk of alienating a lot of customers. But now that Mobile Safari has offline capabilities, that’s no longer a problem.

But it’s the second reason that’s trickier:

Simply put, customers already expected to find us in the App Store and are familiar with what apps can historically offer over websites.

I think this is the biggest challenge facing progressive web apps: battling expectations.

For over a decade, people have formed ideas about what to expect from the web and what to expect from native. From a technical perspective, native and web have become closer and closer in capabilities. But people’s expectations move slower than technological changes.

First of all, there’s the whole issue of discovery: will people understand that they can “install” a website and expect it to behave exactly like a native app? This is where install prompts and ambient badging come in. I think ambient badging is the way to go, but it’s still a tricky concept to explain to people.

But there’s another way of looking at the current situation. Instead of seeing people’s expectations as a negative factor, maybe it’s an opportunity. There’s an opportunity right now for companies to be as groundbreaking and trendsetting as Wired.com when it switched to CSS for layout, or The Boston Globe when it launched its responsive site.

It makes for a great story. Just look at the Pinterest progressive web app for an example (skip to the end to get to the numbers):

Weekly active users on mobile web have increased 103 percent year-over-year overall, with a 156 percent increase in Brazil and 312 percent increase in India. On the engagement side, session length increased by 296 percent, the number of Pins seen increased by 401 percent and people were 295 percent more likely to save a Pin to a board. Those are amazing in and of themselves, but the growth front is where things really shined. Logins increased by 370 percent and new signups increased by 843 percent year-over-year. Since we shipped the new experience, mobile web has become the top platform for new signups. And for fun, in less than 6 months since fully shipping, we already have 800 thousand weekly users using our PWA like a native app (from their homescreen).

Now admittedly their previous mobile web experience was a dreadful doorslam, but still, those are some amazing statistics!

Maybe we’re underestimating the malleability of people’s expectations when it comes to the web on mobile. Perhaps the inertia we think we’re battling against isn’t such a problem as long as we give people a fast, reliable, engaging experience.

If you build that, they will come.

Friday, July 13th, 2018

CSS grid in Internet Explorer 11

When I was in Boston, speaking on a lunchtime panel with Rachel at An Event Apart, we took some questions from the audience about CSS grid. Inevitably, a question about browser support came up—specifically about support in Internet Explorer 11.

(Technically, you can use CSS grid in IE11—in fact it was the first browser to ship a version of grid—but the prefixed syntax is different to the standard and certain features are missing.)

Rachel gave a great balanced response, saying that you need to look at your site’s stats to determine whether it’s worth the investment of your time trying to make a grid work in IE11.

My response was blunter. I said I just don’t consider IE11 as a browser that supports grid.

Now, that might sound harsh, but what I meant was: you’re already dividing your visitors into browsers that support grid, and browsers that don’t …and you’re giving something to those browsers that don’t support grid. So I’m suggesting that IE11 falls into that category and should receive the layout you’re giving to browsers that don’t support grid …because really, IE11 doesn’t support grid: that’s the whole reason why the syntax is namespaced by -ms.

You could jump through hoops to try to get your grid layout working in IE11, as detailed in a three-part series on CSS Tricks, but at that point, the amount of effort you’re putting in negates the time-saving benefits of using CSS grid in the first place.

Frankly, the whole point of prefixed CSS is that is not used after a reasonable amount of time (originally, the idea was that it would not be used in production, but that didn’t last long). As we’ve moved away from prefixes to flags in browsers, I’m seeing the amount of prefixed properties dropping, and that’s very, very good. I’ve stopped using autoprefixer on new projects, and I’ve been able to remove it from some existing ones—please consider doing the same.

And when it comes to IE11, I’ll continue to categorise it as a browser that doesn’t support CSS grid. That doesn’t mean I’m abandoning users of IE11—far from it. It means I’m giving them the layout that’s appropriate for the browser they’re using.

Remember, websites do not need to look exactly the same in every browser.

Wednesday, July 11th, 2018

Links, tags, and feeds

A little while back, I switched from using Chrome as my day-to-day browser to using Firefox. I could feel myself getting a bit too comfortable with one particular browser, and that’s not good. I reckon it’s good to shake things up a little every now and then. Besides, there really isn’t that much difference once you’ve transferred over bookmarks and cookies.

Unfortunately I’m being bitten by this little bug in Firefox. It causes some of my bookmarklets to fail on certain sites with strict Content Security Policies (and CSPs shouldn’t affect bookmarklets). I might have to switch back to Chrome because of this.

I use bookmarklets throughout the day. There’s the Huffduffer bookmarklet, of course, for whenever I come across a podcast episode or other piece of audio that I want to listen to later. But there’s also my own home-rolled bookmarklet for posting links to my site. It doesn’t do anything clever—it grabs the title and URL of the currently open page and pre-populates a form in a new window, leaving me to add a short description and some tags.

If you’re reading this, then you’re familiar with the “journal” section of adactio.com, but the “links” section is where I post the most. Here, for example, are all the links I posted yesterday. It varies from day to day, but there’s generally a handful.

Should you wish to keep track of everything I’m linking to, there’s a twitterbot you can follow called @adactioLinks. It uses a simple IFTTT recipe to poll my RSS feed of links and send out a tweet whenever there’s a new entry.

Or you can drink straight from the source and subscribe to the RSS feed itself, if you’re still rocking it old-school. But if RSS is your bag, then you might appreciate a way to filter those links…

All my links are tagged. Heavily. This is because all my links are “notes to future self”, and all my future self has to do is ask “what would past me have tagged that link with?” when I’m trying to find something I previously linked to. I end up using my site’s URLs as an interface:

At the front-end gatherings at Clearleft, I usually wrap up with a quick tour of whatever I’ve added that week to:

Well, each one of those tags also has a corresponding RSS feed:

…and so on.

That means you can subscribe to just the links tagged with something you’re interested in. Here’s the full list of tags if you’re interested in seeing the inside of my head.

This also works for my journal entries. If you’re only interested in my blog posts about frontend development, you might want to subscribe to:

Here are all the tags from my journal.

You can even mix them up. For everything I’ve tagged with “typography”—whether it’s links, journal entries, or articles—the URL is:

The corresponding RSS feed is:

You get the idea. Basically, if something on my site is a list of items, chances are there’s a corresponding RSS feeds. Sometimes there might even be a JSON feed. Hack some URLs to see.

Meanwhile, I’ll be linking, linking, linking…

Tuesday, July 10th, 2018

Twitter and Instagram progressive web apps

Since support for service workers landed in Mobile Safari on iOS, I’ve been trying a little experiment. Can I replace some of the native apps I use with progressive web apps?

The two major candidates are Twitter and Instagram. I added them to my home screen, and banished the native apps off to a separate screen. I’ve been using both progressive web apps for a few months now, and I have to say, they’re pretty darn great.

There are a few limitations compared to the native apps. On Twitter, if you follow a link from a tweet, it pops open in Safari, which is fine, but when you return to Twitter, it loads anew. This isn’t any fault of Twitter—this is the way that web apps have worked on iOS ever since they introduced their weird web-app-capable meta element. I hope this behaviour will be fixed in a future update.

Also, until we get web notifications on iOS, I need to keep the Twitter native app around if I want to be notified of a direct message (the only notification I allow).

Apart from those two little issues though, Twitter Lite is on par with the native app.

Instagram is also pretty great. It too suffers from some navigation issues. If I click through to someone’s profile, and then return to the main feed, it also loads it anew, losing my place. It would be great if this could be fixed.

For some reason, the Instagram web app doesn’t allow uploading multiple photos …which is weird, because I can upload multiple photos on my own site by adding the multiple attribute to the input type="file" in my posting interface.

Apart from that, though, it works great. And as I never wanted notifications from Instagram anyway, the lack of web notifications doesn’t bother me at all. In fact, because the progressive web app doesn’t keep nagging me about enabling notifications, it’s a more pleasant experience overall.

Something else that was really annoying with the native app was the preponderance of advertisements. It was really getting out of hand.

Well …(looks around to make sure no one is listening)… don’t tell anyone, but the Instagram progressive web app—i.e. the website—doesn’t have any ads at all!

Here’s hoping it stays that way.

Components and concerns

We tend to like false dichotomies in the world of web design and web development. I’ve noticed one recently that keeps coming up in the realm of design systems and components.

It’s about separation of concerns. The web has a long history of separating structure, presentation, and behaviour through HTML, CSS, and JavaScript. It has served us very well. If you build in that order, ensuring that something works (to some extent) before adding the next layer, the result will be robust and resilient.

But in this age of components, many people are pointing out that it makes sense to separate things according to their function. Here’s the Diana Mounter in her excellent article about design systems at Github:

Rather than separating concerns by languages (such as HTML, CSS, and JavaScript), we’re are working towards a model of separating concerns at the component level.

This echoes a point made previously in a slidedeck by Cristiano Rastelli.

Separating interfaces according to the purpose of each component makes total sense …but that doesn’t mean we have to stop separating structure, presentation, and behaviour! Why not do both?

There’s nothing in the “traditonal” separation of concerns on the web (HTML/CSS/JavaScript) that restricts it only to pages. In fact, I would say it works best when it’s applied on smaller scales.

In her article, Pattern Library First: An Approach For Managing CSS, Rachel advises starting every component with good markup:

Your starting point should always be well-structured markup.

This ensures that your content is accessible at a very basic level, but it also means you can take advantage of normal flow.

That’s basically an application of starting with the rule of least power.

In chapter 6 of Resilient Web Design, I outline the three-step process I use to build on the web:

  1. Identify core functionality.
  2. Make that functionality available using the simplest possible technology.
  3. Enhance!

That chapter is filled with examples of applying those steps at the level of an entire site or product, but it doesn’t need to end there:

We can apply the three‐step process at the scale of individual components within a page. “What is the core functionality of this component? How can I make that functionality available using the simplest possible technology? Now how can I enhance it?”

There’s another shared benefit to separating concerns when building pages and building components. In the case of pages, asking “what is the core functionality?” will help you come up with a good URL. With components, asking “what is the core functionality?” will help you come up with a good name …something that’s at the heart of a good design system. In her brilliant Design Systems book, Alla advocates asking “what is its purpose?” in order to get a good shared language for components.

My point is this:

  • Separating structure, presentation, and behaviour is a good idea.
  • Separating an interface into components is a good idea.

Those two good ideas are not in conflict. Presenting them as though they were binary choices is like saying “I used to eat Italian food, but now I drink Italian wine.” They work best when they’re done in combination.

Thursday, July 5th, 2018

The trimCache function in Going Offline

Paul Yabsley wrote to let me know about an error in Going Offline. It’s rather embarrassing because it’s code that I’m using in the service worker for adactio.com but for some reason I messed it up in the book.

It’s the trimCache function in Chapter 7: Tidying Up. That’s the reusable piece of code that recursively reduces the number of items in a specified cache (cacheName) to a specified amount (maxItems). On page 95 and 96 I describe the process of creating the function which, in the book, ends up like this:

 function trimCache(cacheName, maxItems) {
   cacheName.open( cache => {
     cache.keys()
     .then( items => {
       if (items.length > maxItems) {
         cache.delete(items[0])
         .then(
           trimCache(cacheName, maxItems)
         ); // end delete then
       } // end if
     }); // end keys then
   }); // end open
 } // end function

See the problem? It’s right there at the start when I try to open the cache like this:

cacheName.open( cache => {

That won’t work. The open method only works on the caches object—I should be passing the name of the cache into the caches.open method. So the code should look like this:

caches.open( cacheName )
.then( cache => {

Everything else remains the same. The corrected trimCache function is here:

function trimCache(cacheName, maxItems) {
  caches.open(cacheName)
  .then( cache => {
    cache.keys()
    .then(items => {
      if (items.length > maxItems) {
        cache.delete(items[0])
        .then(
          trimCache(cacheName, maxItems)
        ); // end delete then
      } // end if
    }); // end keys then
  }); // end open then
} // end function

Sorry about that! I must’ve had some kind of brainfart when I was writing (and describing) that one line of code.

You may want to deface your copy of Going Offline by taking a pen to that code example. Normally I consider the practice of writing in books to be barbarism, but in this case …go for it.