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Preparing a conference talk

I gave a talk at the State Of The Browser conference in London earlier this month. It was a 25 minute spiel called The Web Is Agreement.

While I was putting the talk together, I posted some pictures of my talk preparation process. People seemed to be quite interested in that peek behind the curtain, so I thought I’d jot down the process I used.

There are two aspects to preparing a talk: the content and the presentation. I like to keep the preparation of those two parts separate. It’s kind of like writing: instead of writing and editing at the same time, it’s more productive to write any old crap first (to get it out of your head) and then go back and edit—”write drunk and edit sober”. Separating out those two mindsets allows you to concentrate on the task at hand.

So, to begin with, I’m not thinking about how I’m going to present the material at all. I’m only concerned with what I want to say.

When it comes to preparing the subject matter for a talk, step number zero is to banish your inner critic. You know who I mean. That little asshole with the sneering voice that says things like “you’re not qualified to talk about this” or “everything has already been said.” Find a way to realise that this demon is a) speaking from inside your head and b) not real. Maybe trying drawing your inner critic. Ridiculous? Yes. Yes, it is.

Alright, time to start. There’s nothing more intimidating than a blank slidedeck, except maybe a blank Photoshop file, or a blank word processing document. In each of those cases, I find that starting with software is rarely a good idea. Paper is your friend.

I get a piece of A3 paper and start scribbling out a mind map. “Mind map” is a somewhat grandiose term for what is effectively a lo-fi crazy wall.

Mind mapping.
Step 1

The idea here is to get everything out of my head. Don’t self-censor. At this stage, there are no bad ideas. This is a “yes, and…” exercise, not a “no, but…” exercise. Divergent, not convergent.

Not everything will make it into the final talk. That’s okay. In fact, I often find that there’s one thing that I’m really attached to, that I’m certain will be in the talk, that doesn’t make the cut. Kill your darlings.

I used to do this mind-mapping step by opening a text file and dumping my thoughts into it. I told myself that they were in no particular order, but because a text file reads left to right and top to bottom, they are in an order, whether I intended it or not. By using a big sheet of paper, I can genuinely get things down in a disconnected way (and later, I can literally start drawing connections).

For this particular talk, I knew that the subject matter would be something to do with web standards. I brain-dumped every vague thought I had about standards in general.

The next step is what I call chunking. I start to group related ideas together. Then I give a label to each of these chunks. Personally, I like to use a post-it note per chunk. I put one word or phrase on the post-it note, but it could just as easily be a doodle. The important thing is that you know what the word or doodle represents. Each chunk should represent a self-contained little topic that you might talk about for 3 to 5 minutes.

Chunking.
Step 2

At this point, I can start thinking about the structure of the talk: “Should I start with this topic? Or should I put that in the middle?” The cost of changing my mind is minimal—I’m just moving post-it notes around.

With topics broken down into chunks like this, I can flesh out each one. The nice thing about this is that I’ve taken one big overwhelming task—prepare a presentation!—and I’ve broken it down into smaller, more manageable tasks. I can take a random post-it note and set myself, say, ten or fifteen minutes to jot down an explanation of it.

The explanation could just be bullet points. For this particular talk, I decided to write full sentences.

Expanding.
Step 3

Even though, in this case, I was writing out my thoughts word for word, I still kept the topics in separate files. That way, I can still move things around easily.

Crafting the narrative structure of a talk is the part I find most challenging …but it’s also the most rewarding. By having the content chunked up like this, I can experiment with different structures. I like to try out different narrative techniques from books and films, like say, flashback: find the most exciting part of the talk; start with that, and then give the backstory that led up to it. That’s just one example. There are many possible narrative stuctures.

What I definitely don’t do is enact the advice that everyone is given for their college presentations:

  1. say what you’re going to say,
  2. say it, and
  3. recap what you’ve said.

To me, that’s the equivalent of showing an audience the trailer for a film right before watching the film …and then reading a review of the film right after watching it. Just play the film! Give the audience some credit—assume the audience has no knowledge but infinite intelligence.

Oh, and there’s one easy solution to cracking the narrative problem: make a list. If you’ve got 7 chunks, you can always give a talk on “Seven things about whatever” …but it’s a bit of a cop-out. I mean, most films have a three-act structure, but they don’t start the film by telling the audience that, and they don’t point out when one act finishes and another begins. I think it’s much more satisfying—albeit more challenging—to find a way to segue from chunk to chunk.

Finding the narrative thread is tricky work, but at least, by this point, it’s its own separate task: if I had tried to figure out the narrative thread at the start of the process, or even when I was chunking things out, it would’ve been overwhelming. Now it’s just the next task in my to-do list.

I suppose, at this point, I might as well make some slides.

Slides.
Step 4

I’m not trying to be dismissive of slides—I think having nice slides is a very good thing. But I do think that they can become the “busy work” of preparing a presentation. If I start on the slides too soon, I find they’ll take up all my time. I think it’s far more important to devote time to the content and structure of the talk. The slides should illustrate the talk …but the slides are not the talk.

If you don’t think of the slides as being subservient to the talk, there’s a danger that you’ll end up with a slidedeck that’s more for the speaker’s benefit than the audience’s.

It’s all too easy to use the slides as a defence mechanism. You’re in a room full of people looking towards you. It’s perfectly reasonable for your brain to scream, “Don’t look at me! Look at the slides!” But taken too far, that can be interpreted as “Don’t listen to me!”

For this particular talk, there were moments when I wanted to make sure the audience was focused on some key point I was making. I decided that having no slide at all was the best way of driving home my point.

But slidedeck style is quite a personal thing, so use whatever works for you.

It’s a similar story with presentation style. Apart from some general good advice—like, speak clearly—the way you present should be as unique as you are. I have just one piece of advice, and it’s this: read Demystifying Public Speaking by Lara Hogan—it’s really, really good!

(I had to apologise to Lara last time I saw her, because I really wanted her to sign my copy of her book …but I didn’t have it, because it’s easily the book I’ve loaned out to other people the most.)

I did a good few run-throughs of my talk. There were a few sentences that sounded fine written down, but were really clumsy to say out loud. It reminded me of what Harrison Ford told George Lucas during the filming of Star Wars: “You can type this shit, George, but you can’t say it.”

I gave a final run-through at work to some of my Clearleft colleagues. To be honest, I find that more nerve-wracking than speaking on a stage in front of a big room full of strangers. I think it’s something to do with the presentation of self.

Finally, the day of the conference rolled around, and I was feeling pretty comfortable with my material. I’m pretty happy with how it turned out. You can read The Web Is Agreement, and you can look at the slides, but as with any conference talk, you kinda had to be there.

Service workers in Samsung Internet browser

I was getting reports of some odd behaviour with the service worker on thesession.org, the Irish music website I run. Someone emailed me to say that they kept getting the offline page, even when their internet connection was perfectly fine and the site was up and running.

They didn’t mind answering my pestering follow-on questions to isolate the problem. They told me that they were using the Samsung Internet browser on Android. After a little searching, I found this message on a Github thread about using waitUntil. It’s from someone who works on the Samsung Internet team:

Sadly, the asynchronos waitUntil() is not implemented yet in our browser. Yes, we will implement it but our release cycle is so far. So, for a long time, we might not resolve the issue.

A-ha! That explains the problem. See, here’s the pattern I was using:

  1. When someone requests a file,
  2. fetch that file from the network,
  3. create a copy of the file and cache it,
  4. return the contents.

Step 1 is the event listener:

// 1. When someone requests a file
addEventListener('fetch', fetchEvent => {
  let request = fetchEvent.request;
  fetchEvent.respondWith(

Steps 2, 3, and 4 are inside that respondWith:

// 2. fetch that file from the network
fetch(request)
.then( responseFromFetch => {
  // 3. create a copy of the file and cache it
  let copy = responseFromFetch.clone();
  caches.open(cacheName)
  .then( cache => {
    cache.put(request, copy);
  })
  // 4. return the contents.
  return responseFromFetch;
})

Step 4 might well complete while step 3 is still running (remember, everything in a service worker script is asynchronous so even though I’ve written out the steps sequentially, you never know what order the steps will finish in). That’s why I’m wrapping that third step inside fetchEvent.waitUntil:

// 2. fetch that file from the network
fetch(request)
.then( responseFromFetch => {
  // 3. create a copy of the file and cache it
  let copy = responseFromFetch.clone();
  fetchEvent.waitUntil(
    caches.open(cacheName)
    .then( cache => {
      cache.put(request, copy);
    })
  );
  // 4. return the contents.
  return responseFromFetch;
})

If a browser (like Samsung Internet) doesn’t understand the bit where I say fetchEvent.waitUntil, then it will throw an error and execute the catch clause. That’s where I have my fifth and final step: “try looking in the cache instead, but if that fails, show the offline page”:

.catch( fetchError => {
  console.log(fetchError);
  return caches.match(request)
  .then( responseFromCache => {
    return responseFromCache || caches.match('/offline');
  });
})

Normally in this kind of situation, I’d use feature detection to check whether a browser understands a particular API method. But it’s a bit tricky to test for support for asynchronous waitUntil. That’s okay. I can use a try/catch statement instead. Here’s what my revised code looks like:

fetch(request)
.then( responseFromFetch => {
  let copy = responseFromFetch.clone();
  try {
    fetchEvent.waitUntil(
      caches.open(cacheName)
      .then( cache => {
        cache.put(request, copy);
      })
    );
  } catch (error) {
    console.log(error);
  }
  return responseFromFetch;
})

Now I’ve managed to localise the error. If a browser doesn’t understand the bit where I say fetchEvent.waitUntil, it will execute the code in the catch clause, and then carry on as usual. (I realise it’s a bit confusing that there are two different kinds of catch clauses going on here: on the outside there’s a .then()/.catch() combination; inside is a try{}/catch{} combination.)

At some point, when support for async waitUntil statements is universal, this precautionary measure won’t be needed, but for now wrapping them inside try doesn’t do any harm.

There are a few places in chapter five of Going Offline—the chapter about service worker strategies—where I show examples using async waitUntil. There’s nothing wrong with the code in those examples, but if you want to play it safe (especially while Samsung Internet doesn’t support async waitUntil), feel free to wrap those examples in try/catch statements. But I’m not going to make those changes part of the errata for the book. In this case, the issue isn’t with the code itself, but with browser support.

A framework for web performance

Here at Clearleft, we’ve recently been doing some front-end consultancy. That prompted me to jot down thoughts on design principles and performance:

We continued with some more performance work this week. Having already covered some of the nitty-gritty performance tactics like font-loading, image optimisation, etc., we wanted to take a step back and formulate an ongoing strategy for performance.

When it comes to web performance, the eternal question is “What should we measure?” The answer to that question will determine where you then concentrate your efforts—whatever it is your measuring, that’s what you’ll be looking to improve.

I started by drawing a distinction between measurements of quantities and measurements of time. Quantities are quite easy to measure. You can measure these quantities using nothing more than browser dev tools:

  • overall file size (page weight + assets), and
  • number of requests.

I think it’s good to measure these quantities, and I think it’s good to have a performance budget for them. But I also think they’re table stakes. They don’t actually tell you much about the impact that performance is having on the user experience. For that, we need to enumerate moments in time:

  • time to first byte,
  • time to first render,
  • time to first meaningful paint, and
  • time to first meaningful interaction.

There’s one more moment in time, which is the time until DOM content is loaded. But I’m not sure that has a direct effect on how performance is perceived, so it feels like it belongs more in the category of quantities than time.

Next, we listed out all the factors that could affect each of the moments in time. For example, the time to first byte depends on the speed of the network that the user is on. It also depends on how speedily your server (or Content Delivery Network) can return a response. Meanwhile, time to first render is affected by the speed of the user’s network, but it’s also affected by how many blocking elements are on the critical path.

By listing all the factors out, we can draw a distinction between the factors that are outside of our control, and the factors that we can do something about. So while we might not be able to do anything about the speed of the user’s network, we might well be able to optimise the speed at which our server returns a response, or we might be able to defer some assets that are currently blocking the critical path.

Factors
1st byte
  • server speed
  • network speed
1st render
  • network speed
  • critical path assets
1st meaningful paint
  • network speed
  • font-loading strategy
  • image optimisation
1st meaningful interaction
  • network speed
  • device processing power
  • JavaScript size

So far, everything in our list of performance-affecting factors is related to the first visit. It’s worth drawing up a second list to document all the factors for subsequent visits. This will look the same as the list for first visits, but with the crucial difference that caching now becomes a factor.

First visit factors Repeat visit factors
1st byte
  • server speed
  • network speed
  • server speed
  • network speed
  • caching
1st render
  • network speed
  • critical path assets
  • network speed
  • critical path assets
  • caching
1st meaningful paint
  • network speed
  • font-loading strategy
  • image optimisation
  • network speed
  • font-loading strategy
  • image optimisation
  • caching
1st meaningful interaction
  • network speed
  • device processing power
  • JavaScript size
  • network speed
  • device processing power
  • JavaScript size
  • caching

Alright. Now it’s time to get some numbers for each of the four moments in time. I use Web Page Test for this. Choose a realistic setting, like 3G on an Android from the East coast of the USA. Under advanced settings, be sure to select “First View and Repeat View” so that you can put those numbers in two different columns.

Here are some numbers for adactio.com:

First visit time Repeat visit time
1st byte 1.476 seconds 1.215 seconds
1st render 2.633 seconds 1.930 seconds
1st meaningful paint 2.633 seconds 1.930 seconds
1st meaningful interaction 2.868 seconds 2.083 seconds

I’m getting the same numbers for first render as first meaningful paint. That tells me that there’s no point in trying to optimise my font-loading, for example …which makes total sense, because adactio.com isn’t using any web fonts. But on a different site, you might see a big gap between those numbers.

I am seeing a gap between time to first byte and time to first render. That tells me that I might be able to get some blocking requests off the critical path. Sure enough, I’m currently referencing an external stylesheet in the head of adactio.com—if I were to inline critical styles and defer the loading of that stylesheet, I should be able to narrow that gap.

A straightforward site like adactio.com isn’t going to have much to worry about when it comes to the time to first meaningful interaction, but on other sites, this can be a significant bottleneck. If you’re sending UI elements in the initial HTML, but then waiting for JavaScript to “hydrate” those elements into working, the user can end up in an uncanny valley of tapping on page elements that look fine, but aren’t ready yet.

My point is, you’re going to see very different distributions of numbers depending on the kind of site you’re testing. There’s no one-size-fits-all metric to focus on.

Now that you’ve got numbers for how your site is currently performing, you can create two new columns: one of those is a list of first-visit targets, the other is a list of repeat-visit targets for each moment in time. Try to keep them realistic.

For example, if I could reduce the time to first render on adactio.com by 0.5 seconds, my goals would look like this:

First visit goal Repeat visit goal
1st byte 1.476 seconds 1.215 seconds
1st render 2.133 seconds 1.430 seconds
1st meaningful paint 2.133 seconds 1.430 seconds
1st meaningful interaction 2.368 seconds 1.583 seconds

See how the 0.5 seconds saving cascades down into the other numbers?

Alright! Now I’ve got something to aim for. It might also be worth having an extra column to record which of the moments in time are high priority, which are medium priority, and which are low priority.

Priority
1st byte Medium
1st render High
1st meaningful paint Low
1st meaningful interaction Low

Your goals and priorities may be quite different.

I think this is a fairly useful framework for figuring out where to focus when it comes to web performance. If you’d like to give it a go, I’ve made a web performance chart for you to print out and fill in. Here’s a PDF version if that’s easier for printing. Or you can download the HTML version if you want to edit it.

I have to say, I’m really enjoying the front-end consultancy work we’ve been doing at Clearleft around performance and related technologies, like offline functionality. I’d like to do more of it. If you’d like some help in prioritising performance at your company, please get in touch. Let’s make the web faster together.

Several people are writing

Anne Gibson writes:

It sounds easy to make writing a habit, but like every other habit that doesn’t involve addictive substances like nicotine or dopamine it’s hard to start and easy to quit.

Alice Bartlett writes:

Anyway, here we are, on my blog, or in your RSS reader. I think I’ll do weaknotes. Some collections of notes. Sometimes. Not very well written probably. Generally written with the urgency of someone who is waiting for a baby wake up.

Patrick Rhone writes:

Bottom line; please place any idea worth more than 280 characters and the value Twitter places on them (which is zero) on a blog that you own and/or can easily take your important/valuable/life-changing ideas with you and make them easy for others to read and share.

Sara Soueidan writes:

What you write might help someone understand a concept that you may think has been covered enough before. We each have our own unique perspectives and writing styles. One writing style might be more approachable to some, and can therefore help and benefit a large (or even small) number of people in ways you might not expect.

Just write.

Even if only one person learns something from your article, you’ll feel great, and that you’ve contributed — even if just a little bit — to this amazing community that we’re all constantly learning from. And if no one reads your article, then that’s also okay. That voice telling you that people are just sitting somewhere watching our every step and judging us based on the popularity of our writing is a big fat pathetic attention-needing liar.

Laura Kalbag writes:

The web can be used to find common connections with folks you find interesting, and who don’t make you feel like so much of a weirdo. It’d be nice to be able to do this in a safe space that is not being surveilled.

Owning your own content, and publishing to a space you own can break through some of these barriers. Sharing your own weird scraps on your own site makes you easier to find by like-minded folks.

Brendan Dawes writes:

At times I think “will anyone reads this, does anyone care?”, but I always publish it anyway — and that’s for two reasons. First it’s a place for me to find stuff I may have forgotten how to do. Secondly, whilst some of this stuff is seemingly super-niche, if one person finds it helpful out there on the web, then that’s good enough for me. After all I’ve lost count of how many times I’ve read similar posts that have helped me out.

Robin Rendle writes:

My advice after learning from so many helpful people this weekend is this: if you’re thinking of writing something that explains a weird thing you struggled with on the Internet, do it! Don’t worry about the views and likes and Internet hugs. If you’ve struggled with figuring out this thing then be sure to jot it down, even if it’s unedited and it uses too many commas and you don’t like the tone of it.

Khoi Vinh writes:

Maybe you feel more comfortable writing in short, concise bullets than at protracted, grandiose length. Or maybe you feel more at ease with sarcasm and dry wit than with sober, exhaustive argumentation. Or perhaps you prefer to knock out a solitary first draft and never look back rather than polishing and tweaking endlessly. Whatever the approach, if you can do the work to find a genuine passion for writing, what a powerful tool you’ll have.

Amber Wilson writes:

I want to finally begin writing about psychology. A friend of mine shared his opinion that writing about this is probably best left to experts. I tried to tell him I think that people should write about whatever they want. He argued that whatever he could write about psychology has probably already been written about a thousand times. I told him that I’m going to be writer number 1001, and I’m going to write something great that nobody has written before.

Austin Kleon writes:

Maybe I’m weird, but it just feels good. It feels good to reclaim my turf. It feels good to have a spot to think out loud in public where people aren’t spitting and shitting all over the place.

Tim Kadlec writes:

I write to understand and remember. Sometimes that will be interesting to others, often it won’t be.

But it’s going to happen. Here, on my own site.

You write…

The top four web performance challenges

Danielle and I have been doing some front-end consultancy for a local client recently.

We’ve both been enjoying it a lot—it’s exhausting but rewarding work. So if you’d like us to come in and spend a few days with your company’s dev team, please get in touch.

I’ve certainly enjoyed the opportunity to watch Danielle in action, leading a workshop on refactoring React components in a pattern library. She’s incredibly knowledgable in that area.

I’m clueless when it comes to React, but I really enjoy getting down to the nitty-gritty of browser features—HTML, CSS, and JavaScript APIs. Our skillsets complement one another nicely.

This recent work was what prompted my thoughts around the principles of robustness and least power. We spent a day evaluating a continuum of related front-end concerns: semantics, accessibility, performance, and SEO.

When it came to performance, a lot of the work was around figuring out the most suitable metric to prioritise:

  • time to first byte,
  • time to first render,
  • time to first meaningful paint, or
  • time to first meaningful interaction.

And that doesn’t even cover the more easily-measurable numbers like:

  • overall file size,
  • number of requests, or
  • pagespeed insights score.

One outcome was to realise that there’s a tendency (in performance, accessibility, or SEO) to focus on what’s easily measureable, not because it’s necessarily what matters, but precisely because it is easy to measure.

Then we got down to some nuts’n’bolts technology decisions. I took a step back and looked at the state of performance across the web. I thought it would be fun to rank the most troublesome technologies in order of tricksiness. I came up with a top four list.

Here we go, counting down from four to the number one spot…

4. Web fonts

Coming in at number four, it’s web fonts. Sometimes it’s the combined weight of multiple font files that’s the problem, but more often that not, it’s the perceived performance that suffers (mostly because of when the web fonts appear).

Fortunately there’s a straightforward question to ask in this situation: WWZD—What Would Zach Do?

3. Images

At the number three spot, it’s images. There are more of them and they just seem to be getting bigger all the time. And yet, we have more tools at our disposal than ever—better file formats, and excellent browser support for responsive images. Heck, we’re even getting the ability to lazy load images in HTML now.

So, as with web fonts, it feels like the impact of images on performance can be handled, as long as you give them some time and attention.

2. Our JavaScript

Just missing out on making the top spot is the JavaScript that we send down the pipe to our long-suffering users. There’s nothing wrong with the code itself—I’m sure it’s very good. There’s just too damn much of it. And that’s a real performance bottleneck, especially on mobile.

So stop sending so much JavaScript—a solution as simple as Monty Python’s instructions for playing the flute.

1. Other people’s JavaScript

At number one with a bullet, it’s all the crap that someone else tells us to put on our websites. Analytics. Ads. Trackers. Beacons. “It’s just one little script”, they say. And then that one little script calls in another, and another, and another.

It’s so disheartening when you’ve devoted your time and energy into your web font loading strategy, and optimising your images, and unbundling your JavaScript …only to have someone else’s JavaScript just shit all over your nice performance budget.

Here’s the really annoying thing: when I go to performance conferences, or participate in performance discussions, you know who’s nowhere to be found? The people making those third-party scripts.

The narrative around front-end performance is that it’s up to us developers to take responsibility for how our websites perform. But by far the biggest performance impact comes from third-party scripts.

There is a solution to this, but it’s not a technical one. We could refuse to add overweight (and in many cases, unethical) third-party scripts to the sites we build.

I have many, many issues with Google’s AMP project, but I completely acknowledge that it solves a political problem:

No external JavaScript is allowed in an AMP HTML document. This covers third-party libraries, advertising and tracking scripts. This is A-okay with me.

The reasons given for this ban are related to performance and I agree with them completely. Big bloated JavaScript libraries are one of the biggest performance killers on the web.

But how can we take that lesson from AMP and apply it to all our web pages? If we simply refuse to be the one to add those third-party scripts, we get fired, and somebody else comes in who is willing to poison web pages with third-party scripts. There’s nothing to stop companies doing that.

Unless…

Suppose we were to all make a pact that we would stand in solidarity with any of our fellow developers in that sort of situation. A sort of joining-together. A union, if you will.

There is power in a factory, power in the land, power in the hands of the worker, but it all amounts to nothing if together we don’t stand.

There is power in a union.

Robustness and least power

There’s a great article by Steven Garrity over on A List Apart called Design with Difficult Data. It runs through the advantages of using unusual content to stress-test interfaces, referencing Postel’s Law, AKA the robustness principle:

Be conservative in what you send, be liberal in what you accept.

Even though the robustness principle was formulated for packet-switching, I see it at work in all sorts of disciplines, including design. A good example is in best practices for designing forms:

Every field you ask users to fill out requires some effort. The more effort is needed to fill out a form, the less likely users will complete the form. That’s why the foundational rule of form design is shorter is better — get rid of all inessential fields.

In other words, be conservative in the number of form fields you send to users. But then, when it comes to users filling in those fields:

It’s very common for a few variations of an answer to a question to be possible; for example, when a form asks users to provide information about their state, and a user responds by typing their state’s abbreviation instead of the full name (for example, CA instead of California). The form should accept both formats, and it’s the developer job to convert the data into a consistent format.

In other words, be liberal in what you accept from users.

I find the robustness principle to be an immensely powerful way of figuring out how to approach many design problems. When it comes to figuring out what specific tools or technologies to use, there’s an equally useful principle: the rule of least power:

Choose the least powerful language suitable for a given purpose.

On the face of it, this sounds counter-intuitive; why forego a powerful technology in favour of something less powerful?

Well, power comes with a price. Powerful technologies tend to be more complex, which means they can be trickier to use and trickier to swap out later.

Take the front-end stack, for example: HTML, CSS, and JavaScript. HTML and CSS are declarative, so you don’t get as much precise control as you get with an imperative language like JavaScript. But JavaScript comes with a steeper learning curve and a stricter error-handling model than HTML or CSS.

As a general rule, it’s always worth asking if you can accomplish something with a less powerful technology:

In the web front-end stack — HTML, CSS, JS, and ARIA — if you can solve a problem with a simpler solution lower in the stack, you should. It’s less fragile, more foolproof, and just works.

  • Instead of using JavaScript to do animation, see if you can do it in CSS instead.
  • Instead of using JavaScript to do simple client-side form validation, try to use HTML input types and attributes like required.
  • Instead of using ARIA to give a certain role value to a div or span, try to use a more suitable HTML element instead.

It sounds a lot like the KISS principle: Keep It Simple, Stupid. But whereas the KISS principle can be applied within a specific technology—like keeping your CSS manageable—the rule of least power is all about evaluating technology; choosing the most appropriate technology for the task at hand.

There are some associated principles, like YAGNI: You Ain’t Gonna Need It. That helps you avoid picking a technology that’s too powerful for your current needs, but which might be suitable in the future: premature optimisation. Or, as Rachel put it, stop solving problems you don’t yet have:

So make sure every bit of code added to your project is there for a reason you can explain, not just because it is part of some standard toolkit or boilerplate.

There’s no shortage of principles, laws, and rules out there, and I find many of them very useful, but if I had to pick just two that are particularly applicable to my work, they would be the robustness principle and the rule of least of power.

After all, if they’re good enough for Tim Berners-Lee…

Sapiens

I finally got around to reading Sapiens by Yuval Noah Harari. It’s one of those books that I kept hearing about from smart people whose opinions I respect. But I have to say, my reaction to the book reminded me of when I read Matt Ridley’s The Rational Optimist:

It was an exasperating read.

At first, I found the book to be a rollicking good read. It told the sweep of history in an engaging way, backed up with footnotes and references to prime sources. But then the author transitions from relaying facts to taking flights of fancy without making any distinction between the two (the only “tell” is that the references dry up).

Just as Matt Ridley had personal bugbears that interrupted the flow of The Rational Optimist, Yuval Noah Harari has fixated on some ideas that make a mess of the narrative arc of Sapiens. In particular, he believes that the agricultural revolution was, as he describes it, “history’s biggest fraud.” In the absence of any recorded evidence for this, he instead provides idyllic descriptions of the hunter-gatherer lifestyle that have as much foundation in reality as the paleo diet.

When the book avoids that particular historical conspiracy theory, it fares better. But even then, the author seems to think he’s providing genuinely new insights into matters of religion, economics, and purpose, when in fact, he’s repeating the kind of “college thoughts” that have been voiced by anyone who’s ever smoked a spliff.

I know I’m making it sound terrible, and it’s not terrible. It’s just …generally not that great. And when it is great, it only makes the other parts all the more frustrating. There’s a really good book in Sapiens, but unfortunately it’s interspersed with some pretty bad editorialising. I have to agree with Galen Strawson’s review:

Much of Sapiens is extremely interesting, and it is often well expressed. As one reads on, however, the attractive features of the book are overwhelmed by carelessness, exaggeration and sensationalism.

Towards the end of Sapiens, Yuval Noah Harari casts his eye on our present-day world and starts to speculate on the future. This is the point when I almost gave myself an injury with the amount of eye-rolling I was doing. His ideas on technology, computers, and even science fiction are embarrassingly childish and incomplete. And the bad news is that his subsequent books—Home Deus and 21 Lessons For The 21st Century—are entirely speculations about humanity and technology. I won’t be touching those with all the ten foot barge poles in the world.

In short, although there is much to enjoy in Sapiens, particularly in the first few chapters, I can’t recommend it.

If you’re looking for a really good book on the fascinating history of our species, read A Brief History of Everyone Who Ever Lived by Adam Rutherford . That’s one I can recommend without reservation.

Flexibility

Over on A List Apart, you can read the first chapter from Tim’s new book, Flexible Typesetting.

I was lucky enough to get an advance preview copy and this book is ticking all my boxes. I mean, I knew I would love all the type nerdery in the book, but there’s a bigger picture too. In chapter two, Tim makes this provacative statement:

Typography is now optional. That means it’s okay for people to opt out.

That’s an uncomfortable truth for designers and developers, but it gets to the heart of what makes the web so great:

Of course typography is valuable. Typography may now be optional, but that doesn’t mean it’s worthless. Typographic choices contribute to a text’s meaning. But on the web, text itself (including its structural markup) matters most, and presentational instructions like typography take a back seat. Text loads first; typography comes later. Readers are free to ignore typographic suggestions, and often prefer to. Services like Instapaper, Pocket, and Safari’s Reader View are popular partly because readers like their text the way they like it.

What Tim describes there isn’t a cause for frustration or despair—it’s a cause for celebration. When we try to treat the web as a fixed medium where we can dictate the terms that people must abide by, we’re doing them (and the web) a disservice. Instead of treating web design as a pre-made contract drawn up by the designer and presented to the user as a fait accompli, it is more materially honest to treat web design as a conversation between designer and user. Both parties should have a say.

Or as Tim so perfectly puts it in Flexible Typesetting:

Readers are typographers, too.

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.

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!

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.

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!

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.

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.

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…

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.

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.

Speaking my brains in Boston

I was in Boston last week to give a talk. I ended up giving four.

I was there for An Event Apart which was, as always, excellent. I opened up day two with my talk, The Way Of The Web.

This was my second time giving this talk at An Event Apart—the first time was in Seattle a few months back. It was also my last time giving this talk at An Event Apart—I shan’t be speaking at any of the other AEAs this year, alas. The talk wasn’t recorded either so I’m afraid you kind of had to be there (unless you know of another conference that might like to have me give that talk, in which case, hit me up).

After giving my talk in the morning, I wasn’t quite done. I was on a panel discussion with Rachel about CSS grid. It turned out to be a pretty good format: have one person who’s a complete authority on a topic (Rachel), and another person who’s barely starting out and knows just enough to be dangerous (me). I really enjoyed it, and the questions from the audience prompted some ideas to form in my head that I should really note down in a blog post before they evaporate.

The next day, I went over to MIT to speak at Design 4 Drupal. So, y’know, technically I’ve lectured at MIT now.

I wasn’t going to do the same talk as I gave at An Event Apart, obviously. Instead, I reprised the talk I gave earlier this at Webstock: Taking Back The Web. I thought it was fitting given how much Drupal’s glorious leader, Dries, has been thinking about, writing about, and building with the indie web.

I really enjoyed giving this talk. The audience were great, and they had lots of good questions afterwards. There’s a video, which is basically my voice dubbed over the slides, followed by a good half of questions afterwards.

When I was done there, after a brief excursion to the MIT bookstore, I went back across the river from Cambridge to Boston just in time for that evening’s Boston CSS meetup.

Lea had been in touch to ask if I would speak at this meet-up, and I was only too happy to oblige. I tried doing something I’ve never done before: a book reading!

No, not reading from Going Offline, my current book which I should encouraging people to buy. Instead I read from Resilient Web Design, the free online book that people literally couldn’t buy if they wanted to. But I figured reading the philosophical ramblings in Resilient Web Design would go over better than trying to do an oral version of the service worker code in Going Offline.

I read from chapters two (Materials), three (Visions), and five (Layers) and I really, really liked doing it! People seemed to enjoy it too—we had questions throughout.

And with that, my time in Boston was at an end. I was up at the crack of dawn the next morning to get the plane back to England where Ampersand awaited. I wasn’t speaking there though. I thoroughly enjoyed being an attendee and absorbing the knowledge bombs from the brilliant speakers that Rich assembled.

The next place I’m speaking will much closer to home than Boston: I’ll be giving a short talk at Oxford Geek Nights on Wednesday. Come on by if you’re in the neighbourhood.

Name That Script! by Trent Walton

Trent is about to pop his AEA cherry and give a talk at An Event Apart in Boston. I’m going to attempt to liveblog this:

How many third-party scripts are loading on our web pages these days? How can we objectively measure the value of these (advertising, a/b testing, analytics, etc.) scripts—considering their impact on web performance, user experience, and business goals? We’ve learned to scrutinize content hierarchy, browser support, and page speed as part of the design and development process. Similarly, Trent will share recent experiences and explore ways to evaluate and discuss the inclusion of 3rd-party scripts.

Trent is going to speak about third-party scripts, which is funny, because a year ago, he never would’ve thought he’d be talking about this. But he realised he needed to pay more attention to:

any request made to an external URL.

Or how about this:

A resource included with a web page that the site owner doesn’t explicitly control.

When you include a third-party script, the third party can change the contents of that script.

Here are some uses:

  • advertising,
  • A/B testing,
  • analytics,
  • social media,
  • content delivery networks,
  • customer interaction,
  • comments,
  • tag managers,
  • fonts.

You get data from things like analytics and A/B testing. You get income from ads. You get content from CDNs.

But Trent has concerns. First and foremost, the user experience effects of poor performance. Also, there are the privacy implications.

Why does Trent—a designer—care about third party scripts? Well, over the years, the areas that Trent pays attention to has expanded. He’s progressed from image comps to frontend to performance to accessibility to design systems to the command line and now to third parties. But Trent has no impact on those third-party scripts. That’s very different to all those other areas.

Trent mostly builds prototypes. Those then get handed over for integration. Sometimes that means hooking it up to a CMS. Sometimes it means adding in analytics and ads. It gets really complex when you throw in third-party comments, payment systems, and A/B testing tools. Oftentimes, those third-party scripts can outweigh all the gains made beforehand. It happens with no discussion. And yet we spent half a meeting discussing a border radius value.

Delivering a performant, accessible, responsive, scalable website isn’t enough: I also need to consider the impact of third-party scripts.

Trent has spent the last few months learning about third parties so he can be better equiped to discuss them.

UX, performance and privacy impact

We feel the UX impact every day we browse the web (if we turn off our content blockers). The Food Network site has an intersitial asking you to disable your ad blocker. They promise they won’t spawn any pop-up windows. Trent turned his ad blocker off—the page was now 15 megabytes in size. And to top it off …he got a pop up.

Privacy can harder to perceive. We brush aside cookie notifications. What if the wording was “accept trackers” instead of “accept cookies”?

Remarketing is that experience when you’re browsing for a spatula and then every website you visit serves you ads for spatula. That might seem harmless but allowing access to our browsing history has serious privacy implications.

Web builders are on the front lines. It’s up to us to advocate for data protection and privacy like we do for web standards. Don’t wait to be told.

Categories of third parties

Ghostery categories third-party providers: advertising, comments, customer interaction, essential, site analytics, social media. You can dive into each layer and see the specific third-party services on the page you’re viewing.

Analyse and itemise third-party scripts

We have “view source” for learning web development. For third parties, you need some tool to export the data. HAR files (HTTP ARchive) are JSON files that you can create from most browsers’ network request panel in dev tools. But what do you do with a .har file? The site har.tech has plenty of resources for you. That’s where Trent found the Mac app, Charles. It can open .har files. Best of all, you can export to CSV so you can share spreadsheets of the data.

You can visualise third-party requests with Simon Hearne’s excellent Request Map. It’s quite impactful for delivering a visceral reaction in a meeting—so much more effective than just saying “hey, we have a lot of third parties.” Request Map can also export to CSV.

Know industry averages

Trent wanted to know what was “normal.” He decided to analyse HAR files for Alexa’s top 50 US websites. The result was a massive spreadsheet of third-party providers. There were 213 third-party domains (which is not even the same as the number of requests). There was an average of 22 unique third-party domains per site. The usual suspects were everywhere—Google, Amazon, Facebook, Adobe—but there were many others. You can find an alphabetical index on better.fyi/trackers. Often the lesser-known domains turn out to be owned by the bigger domains.

News sites and shopping sites have the most third-party scripts, unsurprisingly.

Understand benefits

Trent realised he needed to listen and understand why third-party scripts are being included. He found out what tag managers do. They’re funnels that allow you to cram even more third-party scripts onto your website. Trent worried that this was a Pandora’s box. The tag manager interface is easy to access and use. But he was told that it’s more like a way of organising your third-party scripts under one dashboard. But still, if you get too focused on the dashboard, you could lose focus of the impact on load times. So don’t blame the tool: it’s all about how it’s used.

Take action

Establish a centre of excellence. Put standards in place—in a cross-discipline way—to define how third-party scripts are evaluated. For example:

  1. Determine the value to the business.
  2. Avoid redundant scripts and services.
  3. Fit within the established performance budget.
  4. Comply with the organistional privacy policy.

Document those decisions, maybe even in your design system.

Also, include third-party scripts within your prototypes to get a more accurate feel for the performance implications.

On a live site, you can regularly audit third-party scripts on a regular basis. Check to see if any are redundant or if they’re exceeding the performance budget. You can monitor performance with tools like Calibre and Speed Curve to cover the time in between audits.

Make your case

Do competitive analysis. Look at other sites in your sector. It’s a compelling way to make a case for change. WPO Stats is very handy for anecdata.

You can gather comparative data with Web Page Test: you can run a full test, and you can run a test with certain third parties blocked. Use the results to kick off a discussion about the impact of those third parties.

Talk it out

Work to maintain an ongoing discussion with the entire team. As Tim Kadlec says:

Everything should have a value, because everything has a cost.