I share your view that Svelte is a great framework for small projects. It is also really useful if you want to build small standalone javascript widgets. I've used it at work to build a fast video testimonial slider for Shopify [1]. I really liked the component format as we could quickly integrate our code in the existing HTML layout.
The Svelte built-in store has also been useful for us to manage the current state of the application. Overall development with Svelte has been really quick.
What makes something good for small projects? Does that mean it's not good for big projects? What's the difference between big and small projects that makes Svelte good for one and bad for the other?
Svelte doesn't use a virtual DOM and when it compiles, it only targets what you are specifically using it for.
The thing with Svelte is that for a big project (like an SPA) you're going to end up using SvelteKit, because that's where all the development focus is for things like routing etc... and SvelteKit isn't nearly as settled. As in, there aren't developed "patterns" for doing a lot of things yet so it's a lot of trailblazing. There's also some features that are missing and on the roadmap but SvelteKit just hit 1.0 in December (these are usually more obscure things but you will still likely encounter them if you're building something of moderate complexity.)
I still think overall it would be fine to use for a big project, but a year from now I think it will be a much easier choice. Something that is happening right now is a lot of big players in the wider JS ecosystem are transforming from being React specific to framework agnostic:
This has all happened in the last few months. So it's still new, and they're still improving as they move away from being React specific. People rely on those projects. As more move in that direction I think it will become easier and easier.
Honestly, SvelteKit is pretty solid. They took their time trying to make consistent decisions rather than rushing 1.0 out the door and trying to backtrack later. All design decisions were out in the open on GitHub issues, and they spent a really long time looking at other frameworks and what they got right and wrong. The lack of navel gazing was refreshing.
I wasn't dissing SvelteKit. But I've been using it for about 6 months now. It's not perfect. There are currently some things that are very hard to do in SvelteKit that are not hard in other frameworks. It is what it is. That will change over time.
I think experimentation is one of them. being able to easily break backwards APIs to try new things in each version may not be nice for large scale projects. It's nice to try new things, but it can be a maintenance effort in terms of sustainability. and such projects are usually used for a large project so core development can go a certain line. (like google products for angular, facebook products for react). it doesn't seem to apply to this svelte. It is debatable, of course, that it is a negative thing. But I think it's a shortcoming.
One thing that makes Svelte great for embeds is that it has no runtime dependencies, no equivalent of react.js and react-dom.js. It just compiles down to vanilla JS.
May I ask you how did you find the process of programming a Shopify app using Svelte? I have some experience with Svelte and am currently in process of starting development of a new Shopify app, but I basically decided to go with React as they have a lot of documentation and libraries (Polaris, AppBridge) available for it, while on Svelte I would have to do everything from scratch (or at least that's how I understood it from their docs)
EDIT: after reading your comment one more time, I assume you've used Svelte only for a small part of the app, not the app as a whole?
We are using next.js for the admin interface of the app. Works great with Polaris and AppBridge. Svelte is only used for the widget we are providing to the merchants.
Just noticed your website checker might have a bug: https://onlineornot.com/website-down-checker?requestId=Kfd51...