feat(create): provide svelte config in vite.config.js during create

[manuel3108]

Relates #1111
Discards: #1117
(let's try and create multiple small prs)

Description

I absolutely do not understand why we had so many svelte.config.js's flying around, especially since they were all close to identical. Therefore removed most of them. Since everything in the vite.config is js based, there is no need to bother about .ts extensions during create.

---

JYC update:

• even if vite.config.ts has no typescript today, when I select ts, I expect to have it in ts (and it's today's behavior). Let's keep it here.
• added a util for svelteConfig & updated all addons

Todos:

• playground test reading vite config, needs @sveltejs/load-config
• snapshots
• changeset

Sources:

• Importing Svelte(Kit) settings from the Vite config eslint-plugin-svelte#1550
• feat: support reading Svelte config from vite.config.js/ts language-tools#3031
• feat: support passing Svelte(Kit) config via Vite plugin kit#15944

Checklist

• Update snapshots (if applicable)
• Add a changeset (if applicable)
• Allow maintainers to edit this PR
• I care about what I'm doing, no matter the tool I use (Notepad, Sublime, VSCode, AI...)

[changeset-bot]

🦋 Changeset detected

Latest commit: c5aa89e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
sv	Minor
@sveltejs/sv-utils	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-cli-1119-svelte.vercel.app/

[manuel3108]

Ran some local tests, and everything is working perfectly fine, as soon as those (optional) comments are adressed, im fine by you merging this!

Also lets keep it minor as you suggested.

Can't approve since im the author

[hyunbinseo]

Does eslint.config.js file no longer need svelteConfig imported from svelte.config.js?

The import is removed but the following issue is not closed yet:

• Importing Svelte(Kit) settings from the Vite config eslint-plugin-svelte#1550
• hyunbinseo/svelte-kit-templates@5193ee5 - see diff here or in this PR's snapshot

Would love a clearer instruction for those who want to upgrade.

e.g. the svelteConfig is no longer needed if peer deps are upgraded to ~

[jycouet]

The import isn't gone - it's conditional.

sv now stores config in vite.config.js and ships no svelte.config.js. The eslint addon only adds the svelteConfig import when a real svelte.config.{js,ts} exists. With config in vite.config.js there's nothing importable, so we omit it on purpose: svelte-eslint-parser falls back to its defaults.

Upgrading an existing project:

• Keep your svelte.config.js? Nothing to do - the import stays wired.
• Moved config into vite.config.js and deleted svelte.config.js? Drop the import svelteConfig ... line and the svelteConfig entry in parserOptions. The parser defaults take over.

[hyunbinseo]

explicitly importing allows for better compatibilty and functionality with rules and other tooling that depend on the config file. source

If I understood correctly:

1. The explicit import is for better compatibility
2. Svelte config defined in vite.confit.{js,ts} cannot be imported
3. So the default eslint-plugin-svelte options are used for now
4. If the following issue is resolved, explicit importing can be done, changing the status of 2

• Importing Svelte(Kit) settings from the Vite config eslint-plugin-svelte#1550