If you think 'helping developers meet their legal obligations to build sites that can be used by everyone' is 'woke', then you should go and use a different framework.
> I have no doubts they'll do the same with Nuxt, demanding they implement features that solely exist to pad out hosting costs while providing next to no actual benefits to end users and devs
has that happened with Svelte?
> they now have a monopoly over the most popular frontend meta frameworks (Next, Svelte/Kit, Nuxt, Astro)
Yes. There are features that have been deliberately kept on the platform level to force you to use the platform instead of implementing it on the framework level or guiding you through it with the docs.
ISR _can't_ be implemented at a framework level without tying the framework to the platform. The fact that we instead chose to implement it via a platform-agnostic adapter API surely demonstrates the opposite of what you're implying
> $:{} for example is not explicit, I'd much rather use a slightly longer token (like useEffect) to help document what's going on
FWIW you're describing a legacy syntax — modern Svelte has explicit effects, and addresses your other concerns. I think you'll find it's much more to your liking https://svelte.dev/docs/svelte/$effect
Ha, did not expect this to be on the front page of HN today! Some quick context: in January I was in London for a few days, and while I was there we had a Svelte Society London event.
It's deliberately brief and vague in parts, because it's designed to spur conversation. It's not set in stone, nor is it an Official Statement on behalf of the Svelte team — it's an attempt to articulate the way that the maintainers tend to find ourselves thinking about some of these topics, as viewed through my personal lens. If it helps explain why you like Svelte, great! If it helps explain why you hate it, that's great too — that's the whole point. Have fun with it, and if there are parts you disagree with then your homework is to think through what kind of tenets would describe your ideal framework.
Thank you for creating Svelte. I have basic web dev experience using no-framework. Is there any high level overview article explaining how Svelte compiler transpiles Svelte file into a series of html,css and javascript and wires them up together?
Michel and I have been internet acquaintances for years, and we've even talked about this stuff IRL. MobX certainly isn't something we just somehow never learned about!
But anyway: it's absurd to compare this with React+MobX. MobX replaces useState, sure, but you're still re-rendering entire components on each change (which is why MobX explicitly recommends that you break apart your app into many small components, regardless of whether that's a boon to readability and maintainability.
By contrast, Svelte (and Solid, and other frameworks) understand signals on a much deeper and more optimal level. They're really not the same thing at all.
> MobX replaces useState, sure, but you're still re-rendering entire components on each change (which is why MobX explicitly recommends that you break apart your app into many small components, regardless of whether that's a boon to readability and maintainability.
This is not true. MobX has had an `<Observer>` component for years now. You can be as fine detailed as you wish with rerenders in a larger component.
Unlike Redux at that time (~2016), it was a first approach where minimum rendering was happening effortlessly.
You can have a list of components where each component references a bit of global state and rerenders only if that bit changes, even though the list might have enlarged or other elements changed.
Last time I used it (2016-2020), they used all of the tricks of the trade, get, set object attributes, dropped decorators and it still worked the same.
Notice that you just said "You can have a list of components _where each component_ references a bit of global state". In other words, in order to avoid re-rendering everything, you need to have a component for each item in the list.
In React, the component is the unit of re-rerendering. MobX can't change that fact. The only thing you can do is work around it with hacks that imperatively update the DOM.
Yes, this clarifies what you've meant and I can see the case that is not covered with MobX+React but I assume it is covered by Svelte's runes.
You're saying that I can have the whole app written in a single file without any separation and the updates will still happen only in the place that needs it.
That makes sense. With MobX, this could be done but not with React and not without a bunch of boilerplate that obtains html elements that are referencing the state.
>With MobX, this could be done but not with React and not without a bunch of boilerplate that obtains html elements that are referencing the state.
It's trivial with MobX. The Observer component essentially gives you an "inline" component wherever you need reactivity, without the need to actually componentize.
Cool, did not know that, last time I seriously used MobX was on 2016 primitives. But I see it works similarly to before. All of the accesses will be figured out during the first render.
Observer component is so simple. Just a deferred function invoke. Could have been done with 2016 primitives too.
Hi! First up — not that it matters, but since people will wonder — our design wasn't informed by the Reactivity Transform. We evaluated something close to 50 designs, some of them extremely wacky, before settling on runes, and it wasn't until after that time that the Reactivity Transform was brought to our attention.
Nevertheless, it's interesting and validating that we landed on such similar approaches. While the Reactivity Transform failed, it did so for reasons that I don't think apply to us:
- $state and $ref are quite different. $state doesn't give you access to the underlying object, so there's no conversion necessary between reactive variables and ref objects (either in your head or in code).
- There's strict read/write separation. Anyone with access to a ref has the ability to change its value, which definitely causes problems at scale. It's something that React, Solid and Svelte 5 get right.
- Reactivity Transform introduces things like $() for magic destructuring and $$() for preserving reactivity across boundaries. We're instead encouraging people to use familiar JavaScript concepts like functions and accessors
- There are already a lot of different ways to work with Vue — SFCs vs non-SFCs, template syntax vs JSX, composition API vs options API, `<script>` vs `<script setup>`... on top of that, adding a new compiler mode that needs to interoperate with everything else is inevitably going to be a challenge. This isn't the case with Svelte. While both runes and non-runes mode will be supported for the next two major versions, meaning there will be some short term fragmentation, we've made it clear that runes are the future of Svelte.
I wouldn't say they are "different" - they are fundamentally the same thing: compiler-enabled reactive variables backed by runtime signals! But yes, Vue already exposes the underlying concept of refs, so for users it's two layers of abstractions. This is something that Svelte doesn't suffer from at this moment, but I suspect you will soon see users reinventing the same primitive in userland.
> There's strict read/write separation
I'd argue this is something made more important than it seems to be - we've hardly seen real issues caused by this in real world cases, and you can enforce separation if you want to.
> We're instead encouraging people to use familiar JavaScript concepts like functions and accessors
This is good (despite making exposing state much more verbose). In Vue, we had to introduce destructuring macros because we wanted the transform to be using the same return shape with all the existing composable functions like VueUse.
> There are already a lot of different ways to work with Vue
This is largely because Vue has a longer history, more legacy users that we have to cater to, so it's much harder to get rid of old cruft. We also support cases that Svelte doesn't account for, e.g. use without a compile step. That said, the default way with a compile step is now clearly Composition API + <script setup>. Reactivity Transform also only really applied in this case so the point you raised is kinda moot.
Separate from the above points, the main reason Reactivity Transform wasn't accepted remains in Runes: the fact that compiler-magic now invades normal JS/TS files and alters vanilla semantics. Variable assignments can now potentially be reactive - but there is no obvious indication other than the declaration site. We had users trying Reactivity Transform on large production codebases, and they ended up finding their large composition functions harder to grasp due to exactly this (and not any of the points raised above).
In Svelte 4, the let counter = 0 syntax is already reactive by default, a feature enabled by the compiler. This has been the status quo for Svelte prior to the rune change. The introduction of the $state(0) rune actually provides more hints about its reactivity than before, and restore the original meaning of let counter = 0 (in rune mode). While it's true that the compiler's "invasion" into JS/TS syntax has been a point of discussion, this invasion has been happening for a while, and the initial shock wave has been well-absorbed by the community.
Interestingly, the new changes could be seen as a retreat from that initial invasion, likely triggering a different response from the community. In fact, the resistance I've seen (and my own as well) has been in the opposite direction—it's hating this retreat, complaining Svelte becoming less "magical." and more close to regular joe Javascript.
I’m specifically taking about non-component context, i.e. plain JS/TS files.
Previously Svelte was able to get a pass on this because magic only happens in svelte files - but in the future, any JS/TS files in a rune-enabled Svelte project will technically be SvelteScript, this never happened before and I doubt the community has already “absorbed” how significant this change is.
This is a really great point. I think something like a `.svelte.js` file extension is warranted here. This would key tooling to when it needs to interpret runes, and makes it clear which files in a codebase require the svelte compiler. These files clearly aren't just js/ts at this point, but I think its fine as long as they're marked as such. Custom react hooks, for instance, aren't usable outside of the runtime but can be transpiled without issues by esbuild/tsc and interpreted correctly by a js/ts language server.
As long as it's marked separately from js/ts I don't think its a huge issue though. Svelte files already have script tags that aren't completely vanilla js/ts.
FWIW you can of course implement createSignal in four lines of code, if you prefer the ergonomics of that:
function createSignal(initial) {
let value = $state(initial);
return [() => value, (v) => value = $state(v)];
}
Note that the Solid change is _not_ 'one step' — the `completed` property is being turned from a property to a function, which means you must update all the usage sites as well. Using getters and setters also allows you to use Svelte's convenient `bind:value` approach, which is much less verbose than using the equivalent event handler code. And don't get me started on the [type narrowing issues](https://www.typescriptlang.org/play?#code/C4TwDgpgBA4hzAgJwD...).
There's nothing _wrong_ with the Solid approach, but the ergonomics aren't to our liking. If we need to take a hit in terms of verbosity, we'd rather do it once at the declaration site than n times at every usage site.
These are great points! Thanks for the super thoughtful reply. I'm actually sold.
1. It's really nice that it's so easy to make a `createSignal`
2. I didn't realize that in Solid you had to update all the usage sites too, so now I'd rather stick to the Svelte usage. Nested reactivity is not as effortless as I thought in Solid.
get done() { return done },
set done(value) { done = value },
get text() { return text },
set text(value) { text = value }
Looks a bit boilerplate-y maybe, but keeping your preoptimized call sites is totally worth it.
This might be common enough that some syntax sugar might be worth it?
The short hand for:
todos = [...todos, {
get done() { return done },
set done(value) { done = value },
get text() { return text },
set text(value) { text = value }
}];
> Can you build a $derived from multiple other $derived?
Yes
> Will the end result see temporary, half-updated values?
No. It uses a push-pull mechanism — dependency changes don't result in a re-evaluation until something asks for the value, meaning derivations are 'glitch-free'
