Ref #4329

I didn't document it yet as it's still experimental. I'd also like to get feedback about using it with Vitest, Storybook, etc.

You should be able to use it with a vite.config.js that looks like:

import { sveltekit } from '@sveltejs/kit/experimental/vite';

export default {
  plugins: [ sveltekit() ]
};

For example, you can run the kit.svelte.dev site with the following vite.config.js after removing the vite config from svelte.config.js:

import * as path from 'path';
import { sveltekit } from '@sveltejs/kit/experimental/vite'
import { imagetools } from 'vite-imagetools';

export default {
	plugins: [ imagetools(), sveltekit() ],

	resolve: {
		alias: {
			$img: path.resolve('src/images')
		}
	},

	server: {
		fs: {
			strict: false
		}
	}
};

Some of this code may be able to be cleaned up when we drop support for vite config in svelte.config.js. We may also be able to cleanup some vite-plugin-svelte code if this proposal moves forward: vitejs/vite#8509

Update: this now supports preview as well (#5170) as dev and build