Tags: javascript

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Friday, July 20th, 2018

Short note on progressive ARIA by The Paciello Group

Léonie makes a really good point here: if you’re adding aria attributes to indicate interactions you’re making available through JavaScript, then make sure you also use JavaScript to add those aria attributes.

Thursday, July 19th, 2018

React is just JavaScript – YLD Engineering Blog – Medium

I like that this introduction to React doesn’t assume any knowledge (or desire) to create an entire app from scratch through command line invocations. Instead, here’s a clear explanation of how you can add React—which is, after all, some JavaScript—to an existing project. Oh, and you can write your CSS in CSS.

(Caveat: because everything’s happening in script elements in the browser, what’s outlined here will only do client-side rendering.)

Friday, July 13th, 2018

CSS: A New Kind Of JavaScript | HeydonWorks

A bold proposal by Heydon to make the process of styling on the web less painful and more scalable. I think it’s got legs, but do we really need another three-letter initialism?

We waste far too much time writing and maintaining styles with JavaScript, and I think it’s time for a change. Which is why it’s my pleasure to announce an emerging web standard called CSS.

Tuesday, July 10th, 2018

Web Components in 2018 - Blog | SitePen

A good explanation of web components, complete with some code examples.

Web Components are not a single technology. Instead, they are series of browser standards defined by the W3C allowing developers to build components in a way the browser can natively understand. These standards include:

  • HTML Templates and Slots – Reusable HTML markup with entry points for user-specific markup
  • Shadow DOM – DOM encapsulation for markup and styles
  • Custom Elements – Defining named custom HTML elements with specific behaviour

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.

Monday, July 9th, 2018

Solving Sol

Browser implementations of Sol LeWitt’s conceptual and minimal art, many of which only exist as instructions like this:

Vertical lines, not straight, not touching, covering the wall evenly.

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(keys => {
      if (keys.length > maxItems) {
        cache.delete(keys[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.

Wednesday, July 4th, 2018

Going Offline - Polytechnic

This is a lovely review of Going Offline from Garrett:

With his typical self-effacing humour (chapter titles include Making Fetch Happen and Cache Me If You Can), and easy manner, Jeremy explains how Service Workers, uh, work, the clever things you can do with them, and most importantly, how to build your own.

Best of all, he’s put it into action!

To that end, this site now has its own home-grown, organic, corn fed, Service Worker.

Tuesday, June 26th, 2018

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.

Saturday, June 23rd, 2018

I Don’t Believe in Full-Stack Engineering • Robin Rendle

A good ol’ rant from Robin.

HTML and CSS and JavaScript have always been looked down upon by many engineers for their quirks. When they see a confusing and haphazardly implemented API across browsers (HTML/CSS/JS), I see a swarming, writhing, and constantly improving interface that means we can read stuff that was written fifteen years ago and our browsers can still parse it.

Before jumping to conclusions, read the whole thing. Robin isn’t having a go at people who consider themselves full-stack developers; he’s having a go at the people who are only hiring back-end developers and expecting them to automatically be “full stack.”

Friday, June 22nd, 2018

Offline-Friendly Forms by Max Böck

A clever use of localStorage to stop data from being lost when your visitors are offline.

Thursday, June 21st, 2018

Generative Artistry

Tutorials for recreating classics of generative art with JavaScript and canvas.

Friday, June 8th, 2018

Registering service workers

In chapter two of Going Offline, I talk about registering your service worker wrapped up in some feature detection:

<script>
if (navigator.serviceworker) {
  navigator.serviceworker.register('/serviceworker.js');
}
</script>

But I also make reference to a declarative way of doing this that isn’t very widely supported:

<link rel="serviceworker" href="/serviceworker.js">

No need for feature detection there. Thanks to the liberal error-handling model of HTML (and CSS), browsers will just ignore what they don’t understand, which isn’t the case with JavaScript.

Alas, it looks like that nice declarative alternative isn’t going to be making its way into browsers anytime soon. It has been removed from the HTML spec. That’s a shame. I have a preference for declarative solutions where possible—they’re certainly easier to teach. But in this case, the JavaScript alternative isn’t too onerous.

So if you’re reading Going Offline, when you get to the bit about someday using the rel value, you can cast a wistful gaze into the distance, or shed a tiny tear for what might have been …and then put it out of your mind and carry on reading.

Monday, June 4th, 2018

Web Components Club – A journal about learning web components

Andy Bell is documenting is journey of getting to grips with web components. I think it’s so valuable to share like this as you’re learning, instead of waiting until you’ve learned it all—the fresh perspective is so useful!

Sunday, June 3rd, 2018

The React is “just” JavaScript Myth - daverupert.com

In my experience, there’s no casual mode within React. You need to be all-in, keeping up with the ecosystem, or else your knowledge evaporates.

I think Dave is right. At this point, it’s possible to be a React developer exclusively.

React is an ecosystem. I feel like it’s a disservice to anyone trying to learn to diminish all that React entails. React shows up on the scene with Babel, Webpack, and JSX (which each have their own learning curve) then quickly branches out into technologies like Redux, React-Router, Immutable.js, Axios, Jest, Next.js, Create-React-App, GraphQL, and whatever weird plugin you need for your app.

And, as Jake points out, you either need to go all in or not at all—you can’t really incrementally add Reactness to an existing project.

Thursday, May 31st, 2018

Design Patterns on CodePen

This ever-growing curated collection of interface patterns on CodePen is a reliable source of inspiration.

UTC is Enough for Everyone, Right?

A wonderful—and humorous—deep dive into all things time-related.

Building a calendar sucks. Like there’s really cool shit you can do, since every calendar out there today is basically straight outta 2005, but at the end of the day you’re stuck dealing with all of the edge cases that all your dork friends have warned you about since the dawn of time. (Like literally, the dawn of time is a separate edge case you have to account for as well.)

This also contains a well-deserved shout-out to ISO 8601:

ISO 8601 is one of my favorite standards and/or RFC out there. And yes, you should definitely have a favorite.

I do have a favourite RFC—ask me about it sometime over a beer.

Wednesday, May 30th, 2018

Solving Life’s Problems with CSS | CSS-Tricks

It turns out that Diana Smith isn’t just a genius with CSS—she’s a fantastic writer too. This post is somehow heartfelt and lighthearted at the same time. It’s also very humorous, but beneath the humour there’s an excellent point here about the rule of least power …and doing things the long, hard, stupid way.

Because something about those limitations just calls to me. I know I’m not alone when I say that a rigid set of restrictions is the best catalyst for creativity. Total artistic freedom can be a paralyzing concept.

That can sometimes be the case with programming. If you have the most powerful programming languages in the world at your disposal, it starts to seem natural that you should then have no difficulty solving any programming problem. With all these amazing tools offering countless solutions to solve the same problem, it’s no wonder that we sometimes freeze up with information overload.

Tuesday, May 29th, 2018

Web Push Notifications Demo | Microsoft Edge Demos

Push notifications explained using astrology. But don’t worry, there’s also some code, just in case you prefer your explanations to also include models that actually work.

Saturday, May 26th, 2018

CSS and Markup in Javascript is an Evolutionary Dead End

The bet to make is that we’re going to see more use of specialized languages. And HTML and CSS are the grandaddy specialized languages that have enough social consensus and capital investment to be the seeds of the next generation.