Trys describes exactly the situation where you really do need to use the Shadow DOM in a web component—as opposed to just sticking to HTML web components—, and that’s when the component is going to be distributed and you have no idea where:
This component needed to be incredibly portable, looking great on any third-party website, in any position, at any viewport, with any amount of content. It had to be a “hyper-responsive” component.
React has become a bloated carcass of false promises, misleading claims, and unending layers of backwards compatibility – the wrong kind of backwards compatibility, as they still occasionally break your fucking code when updating.
Pretty much anything else is a better tool for pretty much any web development task.
This is an interesting thought from Scott: using Shadow DOM in HTML web components but only as a way of providing sort-of user-agent styles:
providing some default, low-specificity styles for our slotted light-dom HTML elements while allowing them to be easily overridden.
So many of the problems and challenges of working with Web Components just fall away when you ditch the shadow DOM and use them as a light wrapper for progressive enhancement.
The main reason I’m so hot on Light DOM is that I find the styling story of Web Components using Shadow DOM annoying.
This is an excellent step-by-step walkthrough by Tess of creating a web component, with real thought given to what should be in the HTML (which will act as a fallback) and what’s better generated in the Shadow DOM (like buttons for interactivity).
This perfectly mirrors something Chris was saying in a recent episode of the Shop Talk Show:
I think of the image comparison one. That’s a classic example in Web component. What’s inside is just two IMG tags. That’s it. When it fails, you don’t want a weird div with little arrows on it being rendered on the page. That’s not doing anything because it has failed to load the JavaScript.
You just take some normal HTML markup, wrap it with a custom element, and then write some JS to add capabilities which you can then style with regular CSS! Everything’s of the Light Side of the Web. No need to pierce the Vale of Shadows or whatever.
I think Eric’s approach here should be the default for most web components: you probably don’t need to mess around with the shadow DOM, and you should definitely be wrapping your web component around existing HTML instead of witing opening and closing tags with nothing in between.
Augment, don’t replace.
This is a great tutorial—I just love the interactive parts that really help make things click.
Greg has done a lot of research into developer frustrations with customising form controls.
My current thinking in this space, and I know some folks will find this controversial, but I think we should completely standardize in-page form controls with no limitations on their styling capabilities. What do I mean by in-page controls? I am referring to any form control or component that is rendered within the content process. This standardization would include the sub-parts and their related states and how these are exposed (probably through CSS psuedo classes or HTML attributes). This will enable the shadow-dom to be encapsulated while providing web developers with a consistent experience to adjust to match their brand and needs of their site/application.
I’ve often said that the goal of a good library should be to make itself redundant. jQuery is the poster child for that, and this article points to web components as the way to standardise what’s already happening in JavaScript frameworks:
Remember when
document.querySelectorfirst got wide browser support and started to end jQuery’s ubiquity? It finally gave us a way to do natively what jQuery had been providing for years: easy selection of DOM elements. I believe the same is about to happen to frontend frameworks like Angular and React.
The article goes on to give a good technical overview of custom elements, templates, and the Shadow DOM, but I was surprised to see it making reference to the is syntax for extending existing HTML elements—I’m pretty sure that that is, sadly, dead in the water.
Bringing gradients back, baby!
This is going to be a handy reference to keep on hand whenever you want a button to actually look like a button.
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
Ana goes into exhaustive detail on all the differences in the shadow DOM and styling of input type="range" across browsers.
I’m totally fine with browsers providing different styling for complex UI elements like this, but I wish they’d at least provide a consistent internal structure and therefore a consistent way of over-riding the default styles. Maybe then people wouldn’t be so quick to abandon native elements like this in favour building their own UI components from scratch—the kind of over-engineering that inevitably ends up being under-engineered.
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.
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.
Can an opinionated flat design still have depth and truly be free of drop shadows?
Scott proposes a technique that mimics atmospheric perspective—y’know, when things in the distance look hazier than things in the foreground.
The fact is, we are surrounded by a world that is full of depth, and very little of it is defined by shadow. If we are going to replace drop shadows in our visual UI metaphors, we should look at other options that create depth in the world around us.
Sometimes our job titles and distinctions feel like the plastic grass in a sushi bento; flimsy and only there for decoration.
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
I love this little markup pattern: simple, accessible and elegant …with some quirky CSS gotchas around styling non-standard prefixed pseudo-elements. They came from the Shadow DOM …dun dun DUN!
I really hope that this is the kind of usage we’ll see for web components: enhancements for the browsers that support them without a good ol’ fashioned fallback for older browsers.