People who have migrated a large enough production codebase to Svelte 5, what's your devex like?
I vastly prefer Svelte, because of how clean the code feels. There's only one component per file, and the syntax looks and writes deceptively like vanilla JS and HTML. There's a bit of mind-warp when you realize Svelte doesn't want you passing components with props as props into another component. Svelte gives you "Snippets" instead, which work for some reusability, but are limited. It sort of forces simplicity on you by design, which I like. Most of React's deep nesting and state management doesn't exist in Svelte and is replaced with simple, better primitives.
The bigger gain though for me was Svelte(kit) vs. Next JS. It's very clear what is on the server and what is on the client, and there's none of that "use client" garbage with silly magic exports for Next JS things. The docs are great.
Svelte's biggest disadvantage is that the UI library ecosystem isn't as large. For me that wasn't as big of an issue because it was my expertise, but everyone else looking for a drop in UI library will find the Svelte versions a little worse than their React counterparts.
Because svelte is compiled, it also is by default very snappy. I think choosing Svelte would likely give most devs a speed boost vs. the spinner soup that I've seen most React projects become. A lot of that is going to be in the skill of the programmer, but I love how fast my app is.
[0]: https://bsky.app/profile/davesnider.com/post/3lkvum6xtjs2e
Is it though? Your `+page.svelte` is rendered on the server as well. Not only `.server.` is run on the server.
If you don't do this in React, its your own fault.
Currently porting to Svelte 5 and it is less elegant in my opinion, but perhaps the problems it tries to solve are for more sophisticated developers and I don't really come across them or have knowledge of them. I would prefer to stay on 4, but I will take Rich's word for it that it will be better long term.
Admittedly complicated components with lots of reactivity can be confusing to follow data changes with lots of $: lines so I have tried to minimise that from the beginning. The Svelte 5 code looks cleaner to follow for onboarding devs that aren't familiar with our codebase yet.
Pretty happy! Just wished they didn’t change their “magic” so often, but it’s the price to pay for innovation—if we can even call frontend development that, which I think we should but many frontend haters around here
Plus they need to invest some serious work onto SvelteKit...
Svelte is great. But if you're in a time crunch and you don't have a specific technical requirement that makes React a bad match, I don't think Svelte is worth it. A big part of the Svelte ecosystem is still using Svelte stores, and I found the "one component per file" paradigm to be a bit limiting.
Just a nitpick, with runes in Svelte 5, stores have largely become obsolete. $state, $derived, and $effect replace most of the needs people would normally use stores for.
I'll add devex extends to TSX/JSX itself too, the editor support and language server experience is miles ahead. Alternative formatters/linters like Deno, Biome, oxc etc. all have great support out of the box too, not so much for svelte.
For when react is a bad match; I'm investigating solid instead for this reason.
The svelte ecosystem is in a particularly unfortunate spot right now comprising of single/few author projects that were starting to stabilise but now have a svelte 4 -> 5 migration shaking things up.