Rewrite Svelte adapter with Svelte v5 syntax

[inokawa]

Related to #323

Try it after v5 becomes popular enough.

[gyzerok]

What qualifies as enough?

Seems like it's quite close to stable and most people use version 5 for new projects.

And so are we and now looking for a virtual list solution. Would it make sense to just wait some weeks/months for the update or better go figure it out by ourselves?

[inokawa]

Svelte 4 syntax seems to work on both 4 and 5, otherwise 5 syntax only works on 5. An OSS should be backward compatible as much as possible so there is no strong reason to migrate for now.

[gyzerok]

@inokawa seems like virtua can't be installed for Svelte 5 project due to dependency conflict, because it expects only version 4 in package.json

❯ npm install virtua
npm error code ERESOLVE
npm error ERESOLVE could not resolve
npm error
npm error While resolving: [email protected]
npm error Found: [email protected]
npm error node_modules/svelte
npm error   peer svelte@"^5.0.0-next.1" from @skeletonlabs/[email protected]
npm error   node_modules/@skeletonlabs/floating-ui-svelte
npm error     @skeletonlabs/floating-ui-svelte@"^0.3.1" from the root project
npm error   peer svelte@"^4.0.0 || ^5.0.0-next.0" from @sveltejs/[email protected]
npm error   node_modules/@sveltejs/kit
npm error     peer @sveltejs/kit@"^2.0.0" from @sveltejs/[email protected]
npm error     node_modules/@sveltejs/adapter-auto
npm error       dev @sveltejs/adapter-auto@"^3.2.3" from the root project
npm error     peer @sveltejs/kit@"^2.0.0" from @sveltejs/[email protected]
npm error     node_modules/@sveltejs/adapter-static
npm error       dev @sveltejs/adapter-static@"^3.0.3" from the root project
npm error     1 more (the root project)
npm error   7 more (@sveltejs/vite-plugin-svelte, ...)
npm error
npm error Could not resolve dependency:
npm error peerOptional svelte@">=4.0" from [email protected]
npm error node_modules/virtua
npm error   virtua@"*" from the root project
npm error
npm error Conflicting peer dependency: [email protected]
npm error node_modules/svelte
npm error   peerOptional svelte@">=4.0" from [email protected]
npm error   node_modules/virtua
npm error     virtua@"*" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
npm error to accept an incorrect (and potentially broken) dependency resolution.

[thevincentlee]

Hi @inokawa, I agree with @gyzerok's suggestion.

I believe it is necessary to be compatible. The Svelte 5 API is now stabilizing. The official team also recommends using Svelte 5 directly, and migration tools have been released.

https://svelte-5-preview.vercel.app/docs/old-vs-new
https://x.com/dummdidumm_/status/1844750782647685151

[inokawa]

The peer dependency issue seems to be not inevitable, because 5.0.0-next.263 doesn't match >=4.0 semver (but 5.0.0 matches it).
npm/npm#8854

So after the Svelte 5.0.0 release would be the reasonable timing to release our v5 components. I'll try to migrate virtua after that timing, of course PR welcome.

[gyzerok]

I think ^4.0.0 || ^5.0.0 could be used to do this