I'm a big web components guy, but calling these web components is a massive stretch of the word component.

The word "component" has to mean something ultimately, and to me the defining feature of a web component is that it's self-contained: it brings along its own dependencies, whether that's JavaScript, templates, CSS, etc. Web components shouldn't require an external framework or external CSS (except for customization by the user) - those things should be implementation details depended on directly by the component.

This here is just CSS using tag names for selectors. The element is doing nothing on its own.

Which is fine! It's just not web components.

edit: Also, don't do this:

    <link-button>
      <a href="">Learn more</a>
    </link-button>

That just adds HTML bloat to the page, something people with a singular focus on eliminating JavaScript often forget to worry about. Too many HTML elements can slow the page to a crawl.

Use classes:

    <a class="button" href="">Learn more</a>

They're meant for this, lighter weight, and highly optimized.

▲ rafram 13 hours ago | parent | next [-]

> To many HTML elements can slow the page to a crawl.

You can read the entirety of War and Peace in a single HTML file: https://standardebooks.org/ebooks/leo-tolstoy/war-and-peace/...

A marketing page, SaaS app landing, etc., will not even begin to approach that size, whether or not you add an extra wrapper around your <a>s.

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shimman 12 hours ago | parent | next [-]

Almost 15,000 elements! I do agree that too many elements can slow a page but from my experience that starts to happen a few hundred thousand elements, at least that's what we'd run into making data visualizations for network topologies (often millions of nodes + edges) but the trick for that was to just render in canvas.

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Etheryte 8 hours ago | parent | prev | next [-]

This is true, yet I've seen plenty of poorly built webapps that manage to run slowly even on a top tier development machine. Never mind what all the regular users will get in that case.

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atoav 12 hours ago | parent | prev | next [-]

This is a wonderful example how people live in the inverse-world.

Marketing is in the end a way of trying to get people to listen, even if you have nothing substantial to say (or if you have something to say, potentially multiply the effect of that message). That means you have to invent a lot of packaging and fluff surrounding the thing you want to sell to change peoples impression independent of the actual substance they will encounter.

This to me is entirely backwards. If you want people to listen focus on your content, then make sure it is presented in a way that serves that content. And if we are talking about text, that is really, really small in terms of data and people will be happy if they can access it quickly and without 10 popups in their face.

Not that I accuse any person in this thread of towing that line, but the web as of today seems to be 99% of unneeded crap, with a tiny sprinkle of irrelevant content.

	▲	j45 10 hours ago \| parent [-]
		The experience also depends on the desired outcome, and who's outcome that is. The marketers? or the readers? Which comes first? How far should it go?

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wnevets 9 hours ago | parent | prev | next [-]

Thank you for this example. I'm going to keep it in mind the next time I asked myself if there are too many elements or not.

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croisillon 11 hours ago | parent | prev [-]

nice, Firefox Reader Mode tells me i need 2968 to 3774 minutes

▲ dfabulich 11 hours ago | parent | prev | next [-]

HTML elements can style themselves now using the @scope rule. (It's Baseline Newly Available.) Unlike the "style" attribute, @scope blocks can include @media and other @ rules. You can't get more self-contained than this.

    <swim-lane>
        <style>
            @scope {
                background: pink;
                b {
                    background: lightblue
                }
                @media (max-width: 650px) {
                    /* Mobile responsive styles */
                }
            }
        </style>
        something <b>cool</b>
    </swim-lane>

You can also extract them to a CSS file, instead.

    @scope (swim-lane) { /* ... */ }

The reason approaches like this continue to draw crowds is that Web Components™ as a term is a confluence of the Custom Elements JS API and Shadow DOM.

Shadow DOM is awful. Nobody should be using it for anything, ever. (It's required for putting child-element "slots" in custom elements, and so nobody should use those, either.) Shadow DOM is like an iframe in your page; styles can't escape the shadow root and they can't get into the shadow root, either. IDs are scoped in shadow roots, too, so the aria-labelledby attribute can't get in or out, either.

@scope is the right abstraction: parent styles can cascade in, but the component's styles won't escape the element, giving you all of the (limited) performance advantages of Shadow DOM with none of the drawbacks.

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no_wizard 8 hours ago | parent | next [-]

Decoupling slots from shadow dom would make custom elements even better.

I love custom elements. For non React.js apps I use them to create islands of reactivity. With Vue each custom element becomes a mini app, and can be easily lazy loaded for example. Due to how Vue 3 works, it’s even easy to share state & routing between them when required.

They should really move the most worthwhile features of shadow dom into custom elements: slots and the template shadow-roots, and associated forms are actually nice.

It’s all the extra stuff, like styling issues, that make it a pain in the behind

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spankalee 7 hours ago | parent [-]

There's really no way to decouple slots for shadow roots.

For slots to work you need a container for the slots that the slotted elements do not belong to, and whose slots are separated from other slot containers. Otherwise you can't make an unambiguous relationship between element and slot. This is why a shadow root is a separate tree.

	▲	dfabulich 6 hours ago \| parent [-]
		Agreed. The way I explain it is: suppose you have a `<super-table>` element, and you have a child slot called, for example, `<super-row-header>`. Presumably you want to write some JS to transform the slotted content in some way, decorating each row with the header the user provided. But, if you do that, what happens to the original `<super-row-header>` element that the user provided? Maybe you'd want to delete it…? But how can you tell the difference between the user removing the `<row-header>` and the custom element removing it in the course of its work? What you'd need is for `<row-header>` to somehow exist and not exist at the same time. Which is to say, you'd have one version of the DOM (the Light DOM) where the slot element exists, and another version of the DOM (the Shadow DOM) where the `<row-header>` element doesn't exist, and the transformed content exists instead. It's clever, I guess, but the drawbacks far outweigh the benefits. Client-side components inherently require JS anyway, so just use your favorite JS framework. Frameworks can't really interoperate while preserving fine-grained reactivity (in fact, Shadow DOM makes that harder), so, just pick a framework and use it.

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spankalee 11 hours ago | parent | prev [-]

That's styling itself sure, but it's not self-evidently self-contained. Does every component emit those styles? Are they in the page stylesheet? How do they get loaded?

Counterpoint: Shadow DOM is great. People should be using it more. It's the only DOM primitive that allows for interoperable composition. Without it you're at the mercy of frameworks for being able to compose container components out of internal structure and external children.

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dfabulich 10 hours ago | parent | next [-]

https://2025.stateofhtml.com/en-US/features/web_components/

Sort by negative sentiment; Shadow DOM is at the top of the list, the most hated feature in Web Components. You can read the comments, too, and they're almost all negative, and 100% correct.

"Accessibility nightmare"

"always hard to comprehend, and it doesn't get easier with time"

"most components don't need it"

"The big issue is you need some better way to some better way to incorporate styling from outside the shadow dom"

> It's the only DOM primitive that allows for interoperable composition.

There is no DOM primitive that allows for interoperable composition with fine-grained reactivity. Your framework offers fine-grained reactivity (Virtual DOM for React/Preact, signals for Angular, runes for Svelte, etc.) and any component that contains another component has to coordinate with it.

As a result, you can only mix-and-match container components between frameworks with different reactivity workflows by giving up on fine-grained reactivity, blowing away the internals when you cross boundaries between frameworks. (And Shadow DOM makes it harder, not easier, to coordinate workflows between frameworks.)

Shadow DOM sucks at the only thing it's supposed to be for. Please, listen to the wisdom of the crowd here.

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spankalee 7 hours ago | parent | next [-]

> There is no DOM primitive that allows for interoperable composition with fine-grained reactivity. Your framework offers fine-grained reactivity (Virtual DOM for React/Preact, signals for Angular, runes for Svelte, etc.) and any component that contains another component has to coordinate with it.

This just isn't true - composition and reactivity are completely orthogonal concerns.

Any reactivity system can manage DOM outside of the component, including nodes that are projected into slots. The component's internal DOM is managed by the component using whatever reactivity system it desires.

There are major applications built this way. They make have a React outer shell using vdom and Lit custom elements using lit-html for their shadow contents.

On top of those basics you can also have cross-shadow interoperable fine-grained reactivity with primitives like signals. You can pass signals around, down the tree, across subtrees, and have different reactivity systems use those signals to update the DOM.

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dfabulich 6 hours ago | parent [-]

You can do it, but that undermines the whole point of React: fine-grained reactivity.

If the child component had been a React component instead, the children would have participated in the virtual DOM, and React could do a minimal DOM update when it was done.

React can't even see the shadow contents of Lit elements, so React just has to update the light DOM and let Lit take over from there.

(Same applies to Vue, Angular, Svelte, Solid, etc. Each framework has a reactivity system, and you have to integrate with it to get its benefits.)

	▲	spankalee 4 hours ago \| parent [-]
		You still get minimal DOM updates crossing shadow boundaries. This is true fact. React's vdom without shadow DOM passes props to components, which all return one big vdom tree, and then there's one big reconciliation. React used with shadow DOM evaluates smaller vdom trees per shadow root, and does more, but smaller reconciliations. It's the same O(n) work. But in reality it's often much _better_ with shadow roots because the common WC base classes like Lit's ReactiveElement all do change detection on a per-property basis. So you only regenerate vdom trees for components with changed props, and with slots that doesn't include children. So if children of a component change, but props don't, the component doesn't need to re-render. You can do something similar by hand with memo, but that doesn't handle children separately. The compiler will, of course, fix everything. Every other reactivity system works fine across shadow boundaries. Even the super-fine grained ones like Solid. The only issue with signals-based libraries like Solid is that they pass signals around instead of values, so to get true no-re-rendering behavior with web components you have to do that to, which means picking a signals library, which means less interoperability. The TC39 signals proposal points to a future where you can do that interoperably too.

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9dev 8 hours ago | parent | prev [-]

I feel like it’s a niche feature that got way too much attention. In a past job, we maintained a widget customers could embed onto their page. How much trouble we had with parent styles creeping into our widget and ruining the layout! This would have been so much easier with shadow DOM effectively isolating it from the customer site; that is the only valid use case for it, I feel.

Yet, for actual web components, I entirely agree with you.

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yawaramin 10 hours ago | parent | prev [-]

Yeah but most people don't need or want 'interoperable composition', they want sites with a consistent look-and-feel. Shadow DOM makes this much more difficult.

	▲	tisdadd 41 minutes ago \| parent [-]
		I haven't played with the Shadow Dom since Polymer one, but we had defaults and variables to address this that worked amazingly, and helped standardize it with other teams far better than other css things we had done at the time. It looks like that is still a thing - https://shadow-style.github.io/ - without which people injected things through the CMS that were not fun to deal with.

▲ lucideer 13 hours ago | parent | prev | next [-]

There's a lot of contradictions in this comment.

> it's self-contained: it brings along its own dependencies, whether that's JavaScript, templates, CSS

> Also, don't do this [...] That just adds HTML bloat to the page, something people with a singular focus on eliminating JavaScript often forget to worry about. To many HTML elements can slow the page to a crawl.

A static JS-less page can handle a lot of HTML elements - "HTML bloat" isn't really a thing unless those HTML elements come with performance-impacting behaviour. Which "self-contained" web-components "bringing along their own dependencies" absolutely will.

> shouldn't require an external framework

If you're "bringing along your own dependencies" & you don't have any external framework to manage those dependencies, you're effectively loading each component instance as a kind of "statically linked" entity, whereby those links are in-memory. That's going to bloat your page enormously in all but the simplest of applications.

▲ graypegg 12 hours ago | parent | prev | next [-]

I might toss it out there that upcoming changes to attr() [0] as well as typed properties [1] will add some interesting features. Being able to provide a value that's subbed into a stylesheet from the HTML itself is neat.

You can try to get by with auto-generated selectors for every possible value today, ([background="#FFFFFF"]{background: #FFFFFF}[background="#FFFFFE"]{background: #FFFFFE}...) but just mapping attributes to styles 1:1 does begin to feel like a very lightweight component.

(Note... I'm not convinced this is a great idea... but it could be interesting to mess around with.)

[0] https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...

[1] https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/A...

▲ akst 10 hours ago | parent | prev | next [-]

I disagree on the number of elements actually approaching problematic territory, but agree this just isn’t something you can’t do already without web components

▲ akagusu 13 hours ago | parent | prev [-]

According to the dictionary, the word component means "a part or element of a larger whole" which I think goes to the opposite direction of "self contained"