[docs] add docs for vite-plugin-svelte

[Mlocik97]

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[dummdidumm]

It's passed to vite-plugin-svelte , not rollup. Does it silence all warnings you filter out through that in both dev mode and build?

[Conduitry]

Above this list, it says that the values below are the defaults. Is this noop function the default value for onwarn? Where's that default coming from? I don't see onwarn mentioned anywhere else in this repo besides in one test.

[dominikg]

Imho kit docs should not include/duplicate documentation for specific vite-plugin-svelte options.

The onwarn option is going to be moved to vitePlugin.onwarn once sveltejs/rfcs#59 lands

Maybe a generic note+link to plugin docs helps? That would avoid having to maintain docs in 2 locations

[dummdidumm]

The onwarn option is going to be moved to vitePlugin.onwarn once sveltejs/rfcs#59 lands

I think onwarn as top level would make sense so language tools can listen to it, too. The rollup/webpack plugins could, too.

[dominikg]

when and if onwarn becomes a standardized top level config key it should be documented properly in sveltejs/config and linked here.

Currently it is an implementation detail of vite-plugin-svelte (and rollup-plugin-svelte). I don't think we should add the actual option here, unless we also want to start adding all other options too, and some more vite ones while we're at it?

Why exactly is this needed? Did we recieve tons of questions about warnings and vite-plugin-svelte docs are not clear enough?

[Mlocik97]

Why exactly is this needed? Did we recieve tons of questions about warnings and vite-plugin-svelte docs are not clear enough?

I saw a quite lot of question about silencing warnings in Discord.

[dominikg]

Why exactly is this needed? Did we recieve tons of questions about warnings and vite-plugin-svelte docs are not clear enough?

I saw a quite lot of question about silencing warnings in Discord.

Please give examples where ignoring the warning is the correct solution. Most of the time warnings do identify actual problems that should be fixed in the code that caused them instead of just ignoring. If there are common "false positives" we should try to avoid issuing that warning altogether instead of leaving it for the user to clean up.

[Mlocik97]

Please give examples where ignoring the warning is the correct solution.

I never said it's correct... I said it's what is often asked for in Discord.

I myself never used onwarn setting...

[bluwy]

Yeah, I agree with dominik that adding just onwarn may be too specific to vite-plugin-svelte (at the current state). However it's still ideal to show how to configure onwarn if it's often a common question asked. I think a small section explaining that the config applies to vite-plugin-svelte too is a nice middle ground, per my comment.

FWIW I had usecases for onwarn too, e.g. silencing them on builds (easier to debug), and silencing warnings from third-party packages (checking warning file path contains node_modules).

[dominikg]

I'm still hesitant to mentioning onwarn, the discussion above indicates it could be abused by novice users to ignore warnings to their own disadvantage.
A generic "there are additional options for vite-plugin-svelte, look here" note is both less effort in the long run and more helpful as the current state of this PR only mentions onwarn.

[dominikg]

Please update to a generic message as discussed in the Conversation above

[ignatiusmb]

This PR is getting too involved for such a straightforward change, we don't want to overwhelm newcomers by having too much information in the face when reading through the docs.

A comment on the config example explaining that options from the plugin can also be passed should be enough, maybe update docs on plugin repo to have an example usage with SK if needed, I left a suggestion to that comment, I'll leave the plugin docs to @dominikg and @bluwy