Tags: webcomponents

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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

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!

Monday, January 22nd, 2018

Bad Month for the Main Thread - daverupert.com

JavaScript is CPU intensive and the CPU is the bottleneck for performance.

I’m on Team Dave.

But darn it all, I just want to build modular websites using HTML and a little bit of JavaScript.

Friday, December 29th, 2017

Raindrops on roses, whiskers on kittens, declarative web APIs and truly serverless web endpoints

Three technologies that Ada is excited about:

  1. a service: IndieAuth,
  2. a front end library: Comlink,
  3. a pattern: APIs as Web Components.

Tuesday, November 28th, 2017

i is=”the walrus”

In which Brian takes a long winding route through an explanation of why the is attribute for custom elements is dead before he demonstrates the correct way to use web components:

<!-- instead of writing this -->
<input type="radio" is="x-radio">

<!-- you write this -->
<x-radio>
<input type="radio">
</x-radio>

Sadly, none of the showcase examples I’ve seen for web components do this.

Thursday, November 9th, 2017

Jeremy Keith on Evaluating Technology at SmashingConf Barcelona 2017 on Vimeo

I think this is the best delivery of this talk I’ve ever given. It was something about being in that wonderful venue.

I got quite worked up around the the 32 minute mark.

Jeremy Keith on Evaluating Technology at SmashingConf Barcelona 2017

Tuesday, November 7th, 2017

Collapsible Sections

The latest edition of Heydon’s Inclusive Components is absolutely fantastic! The pattern itself—toggling sections of content—is quite straightforward, but then there’s a masterclass in how to create a web component that still allows the content to be accessible in older browsers. The key, as ever, is progressive enhancement:

Whether implemented through web components or not, progressive enhancement not only ensures the interface is well-structured and robust. As we’ve seen here, it can also simplify the editorial process. This makes developing the application and its content more inclusive.

Thursday, October 19th, 2017

Mozilla Developer Roadshow Asia Jeremy Keith - YouTube

At the 14 minute mark I had to deal with an obstreperous member of the audience. He wasn’t heckling exactly …he just had a very bad experience with web components, and I think my talk was triggering for him.

Mozilla Developer Roadshow Asia: Jeremy Keith

Monday, October 2nd, 2017

Web Components: The Long Game – Infrequently Noted

One of the things we’d hoped to enable via Web Components was a return to ctrl-r web development. At some level of complexity and scale we all need tools to help cope with code size, application structure, and more. But the tender, loving maintainance of babel and webpack and NPM configurations that represents a huge part of “front end development” today seems…punitive. None of this should be necessary when developing one (or a few) components and composing things shouldn’t be this hard. The sophistication of the tools needs to get back to being proportional with the complexity of the problem at hand.

I completely agree with Alex here. But that’s also why I was surprised and disheartened when I linked to Monica’s excellent introduction to web components that a package manager seemed to be a minimum requirement.

Saturday, August 12th, 2017

Shadow DOM: fast and encapsulated styles – Monica Dinculescu

Monica explains how Shadow DOM could be the perfect answer for scoping CSS:

We didn’t have style encapsulation, so we started naming things “the right way” with BEM, so that we didn’t accidentally stomp over each other’s styles. We wanted to be able to author CSS from inside a JavaScript component, so we started using CSS-in-JS. We needed all these tools, because “the platform” (read: the browsers that be) wasn’t there, and building these tools showed that there was a need to move forward. For style encapsulation, Shadow DOM is the platform moving forward.

Although, in a way, Shadow DOM is also another flavour of CSS-in-JS:

Before you complain that using a Shadow DOM and Web Components means that it absolutely requires JavaScript: this is true.

Tuesday, July 4th, 2017

Jekyll Includes are Cool - daverupert.com

Dave explains how Jekyll Includes are starting to convert him to web components. The encapsulation is nice and neat. And he answers the inevitable “but why not use React?” question:

Writing HTML that contains JavaScript, not JavaScript that contains HTML, feels good to me.

The key feature for me is that this approach doesn’t have to depend on JavaScript in the browser:

I like that Web Components are an entirely client-side technology but can be rendered server-side in existing tech stacks whether it’s Jekyll, Rails, or even some Enterprise Java system.

Monday, June 12th, 2017

An intro to web components with otters – Monica Dinculescu

A really great introduction to web components by Monica. But I couldn’t help but be disheartened by this:

Web components tend to have dependencies on other web components, so you need a package manager to herd all them cats.

For me, this kind of interdependence lessens the standalone nature of web components—it just doesn’t feel quite so encapsulated to me. I know that this can be solved with build tools, but now you’ve got two problems (and one more dependency).

Thursday, November 10th, 2016

Custom Elements: an ecosystem still being worked out - Tales of a Developer Advocate

Really, really smart thinking from Paul here, musing on the power relationship between the creators of custom elements and the users of custom elements.

Sunday, November 6th, 2016

Create a MarkDown tag - JSFiddle

This is nice example of a web component that degrades gracefully—if custom elements aren’t supported, you still get the markdown content, just not converted to HTML.

<ah-markdown>
## Render some markdown!
</ah-markdown>

Friday, October 21st, 2016

The Web Platform Podcast : 111 Extensible Web Components on Huffduffer

I spoke my brains in this podcast episode, all about web components, progressive enhancement and backwards compatibility.

Wednesday, August 24th, 2016

Shadow DOM v1: self-contained web components | Web Fundamentals - Google Developers

An in-depth look at the current Shadow DOM spec. It’s well-written but I don’t think this will really click with me until I start playing around with it for myself.

It’s good to see that the examples have some thought given to fallback content.

There’s also a corresponding tutorial on custom elements

Wednesday, August 3rd, 2016

Extensible web components

Adam Onishi has written up his thoughts on web components and progressive enhancements, following on from a discussion we were having on Slack. He shares a lot of the same frustrations as I do.

Two years ago, I said:

I have conflicting feelings about Web Components. I am simultaneously very excited and very nervous.

I still feel that way. In theory, web components are very exciting. In practice, web components are very worrying. The worrying aspect comes from the treatment of backwards compatibility.

It all comes down to the way custom elements work. When you make up a custom element, it’s basically a span.

<fancy-select></fancy-select>

Then, using JavaScript with ShadowDOM, templates, and the other specs that together make up the web components ecosystem, you turn that inert span-like element into something all-singing and dancing. That’s great if the browser supports those technologies, and the JavaScript executes successfully. But if either of those conditions aren’t met, what you’re left with is basically a span.

One of the proposed ways around this was to allow custom elements to extend existing elements (not just spans). The proposed syntax for this was an is attribute.

<select is="fancy-select">...</select>

Browser makers responded to this by saying “Nah, that’s too hard.”

To be honest, I had pretty much given up on the is functionality ever seeing the light of day, but Monica has rekindled my hope:

Still, I’m not holding my breath for this kind of declarative extensibility landing in browsers any time soon. Instead, a JavaScript-based way of extending existing existing elements is currently the only way of piggybacking on all the accessible behavioural goodies you get with native elements.

class FancySelect extends HTMLSelectElement

But this imperative approach fails completely if custom elements aren’t supported, or if the JavaScript fails to execute. Now you’re back to having spans.

The presentation on web components at the Progressive Web Apps Dev Summit referred to this JavaScript-based extensibility as “progressively enhancing what’s already available”, which is a bit of a stretch, given how completely it falls apart in older browsers. It was kind of a weird talk, to be honest. After fifteen minutes of talking about creating elements entirely from scratch, there was a minute or two devoted to the is attribute and extending existing elements …before carrying as though those two minutes never happened.

But even without any means of extending existing elements, it should still be possible to define custom elements that have some kind of fallback in non-supporting browsers:

<fancy-select>
 <select>...</select>
</fancy-select>

In that situation, you at least get a regular ol’ select element in older browsers (or in modern browsers before the JavaScript kicks in and uplifts the custom element).

Adam has a great example of this in his post:

I’ve been thinking of a gallery component lately, where you’d have a custom element, say <o-gallery> for want of a better example, and simply populate it with images you want to display, with custom elements and shadow DOM you can add all the rest, controls/layout etc. Markup would be something like:

<o-gallery>
 <img src="">
 <img src="">
 <img src="">
</o-gallery>

If none of the extra stuff loads, what do we get? Well you get 3 images on the page. You still get the content, but just none of the fancy interactivity.

Yes! This, in my opinion, is how we should be approaching the design of web components. This is what gets me excited about web components.

Then I look at pretty much all the examples of web components out there and my nervousness kicks in. Hardly any of them spare a thought for backwards-compatibility. Take a look, for example, at the entire contents of the body element for the Polymer Shop demo site:

<shop-app unresolved="">SHOP</shop-app>

This seems really odd to me, because I don’t think it’s a good way to “sell” a technology.

Compare service workers to web components.

First of all, ask the question “who benefits from this technology?” In the case of service workers, it’s the end users. They get faster websites that handle network failure better. In the case of web components, there are no direct end-user benefits. Web components exist to make developers lives easier. That’s absolutely fine, but any developer convenience gained by the use of web components can’t come at the expense of the user—that price is too high.

The next question we usually ask when we’re evaluating a technology is “how well does it work?” Personally, I think it’s just as important to ask “how well does it fail?”

Service workers work well and fail well. If a browser supports service workers, the user gets all the benefits. If a browser doesn’t support service workers, the user get the same experience they would have always had.

Web components (will) work well, but fail badly. If a browser supports web components, the user gets the experience that the developer has crafted using these new technologies. If a browser doesn’t support web components, the user gets …probably nothing. It depends on how the web components have been designed.

It’s so much easier to get excited about implementing service workers. You’ve literally got nothing to lose and everything to gain. That’s not the case with web components. Or at least not with the way they are currently being sold.

See, this is why I think it’s so important to put some effort into designing web components that have some kind of fallback. Those web components will work well and fail well.

Look at the way new elements are designed for HTML. Think of complex additions like canvas, audio, video, and picture. Each one has been designed with backwards-compatibility in mind—there’s always a way to provide fallback content.

Web components give us developers the same power that, up until now, only belonged to browser makers. Web components also give us developers the same responsibilities as browser makers. We should take that responsibility seriously.

Web components are supposed to be the poster child for The Extensible Web Manifesto. I’m all for an extensible web. But the way that web components are currently being built looks more like an endorsement of The Replaceable Web Manifesto. I’m not okay with a replaceable web.

Here’s hoping that my concerns won’t be dismissed as “piffle and tosh” again by the very people who should be thinking about these issues.

Monday, August 1st, 2016

Web Components and progressive enhancement - Adam Onishi

Adam and I share the same hopes and frustrations with web components. They can be written in a resilient, layered way that allows for progressive enhancement, but just about every example out there demonstrates a “my way or the highway” approach to using them.

We were chatting about this in the Design Systems slack channel, and it helped clarify some of my thoughts. I’ll try to poop out a blog post about this soon.

Tuesday, July 26th, 2016

shawnbot/custom-elements: All about HTML Custom Elements

A good introduction to custom elements, one piece of the web components stack.

That said, when using custom elements—or anything involving JavaScript, for that matter—you should always design experiences for progressive enhancement, and plan for the possibility that JavaScript isn’t enabled or available.

Hmmm …that’s kind of hard when JavaScript is required to make custom elements work at all.

Tuesday, July 12th, 2016

How Will Web Components Change CSS Architecture? - Snook.ca

Depending on how you’re currently structuring your CSS and class attributes, web components might not make all that much of a difference to your workflow.