chore!: remove useVitePreprocess (#538)

Author: bluwy

.changeset/fast-ligers-sort.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/vite-plugin-svelte': patch
+---
+
+Remove `experimental.useVitePreprocess` option in favour of `vitePreprocess`

docs/config.md

@@ -244,13 +244,6 @@ export default {
 };
 ```
 
-### useVitePreprocess
-
-- **Type:** `boolean`
-- **Default:** `false`
-
-  Use extra preprocessors that delegate style and TypeScript preprocessing to native Vite plugins. TypeScript will be transformed with esbuild. Styles will be transformed using [Vite's CSS plugin](https://vitejs.dev/guide/features.html#css), which handles `@imports`, `url()` references, PostCSS, CSS Modules, and `.scss`/`.sass`/`.less`/`.styl`/`.stylus` files. Do not use together with TypeScript or style preprocessors from `svelte-preprocess` as attempts to transform the content twice will fail!
-
 ### dynamicCompileOptions
 
 - **Type:**

packages/e2e-tests/import-queries/svelte.config.js

@@ -1,9 +1,7 @@
+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+
 export default {
-	vitePlugin: {
-		experimental: {
-			useVitePreprocess: true
-		}
-	},
+	preprocess: [vitePreprocess()],
 	onwarn(warning, defaultHandler) {
 		// import query test generates one of these
 		if (warning.code === 'custom-element-no-tag') return;

packages/vite-plugin-svelte/src/index.ts

@@ -89,7 +89,6 @@ export function svelte(inlineOptions?: Partial<Options>): Plugin[] {
 				if (isSvelteMetadataChanged) {
 					// Force Vite to optimize again. Although we mutate the config here, it works because
 					// Vite's optimizer runs after `buildStart()`.
-					// TODO: verify this works in vite3
 					viteConfig.optimizeDeps.force = true;
 				}
 			},

packages/vite-plugin-svelte/src/utils/options.ts

@@ -680,15 +680,6 @@ export interface SvelteOptions {
  * These options are considered experimental and breaking changes to them can occur in any release
  */
 export interface ExperimentalOptions {
-	/**
-	 * Use extra preprocessors that delegate style and TypeScript preprocessing to native Vite plugins
-	 *
-	 * Do not use together with `svelte-preprocess`!
-	 *
-	 * @default false
-	 */
-	useVitePreprocess?: boolean;
-
 	/**
 	 * A function to update `compilerOptions` before compilation
 	 *

packages/vite-plugin-svelte/src/utils/preprocess.ts

@@ -1,18 +1,8 @@
 import type { ResolvedConfig, Plugin } from 'vite';
 import MagicString from 'magic-string';
-import { preprocess } from 'svelte/compiler';
 import { PreprocessorGroup, ResolvedOptions } from './options';
 import { log } from './log';
 import path from 'path';
-import { vitePreprocess } from '../preprocess';
-
-function createVitePreprocessorGroup(config: ResolvedConfig): PreprocessorGroup {
-	return {
-		markup({ content, filename }) {
-			return preprocess(content, vitePreprocess({ style: config }), { filename });
-		}
-	};
-}
 
 /**
  * this appends a *{} rule to component styles to force the svelte compiler to add style classes to all nodes
@@ -40,13 +30,6 @@ function buildExtraPreprocessors(options: ResolvedOptions, config: ResolvedConfi
 	const prependPreprocessors: PreprocessorGroup[] = [];
 	const appendPreprocessors: PreprocessorGroup[] = [];
 
-	if (options.experimental?.useVitePreprocess) {
-		log.warn(
-			'`experimental.useVitePreprocess` is deprecated. Use the `vitePreprocess()` preprocessor instead. See https://github.com/sveltejs/vite-plugin-svelte/blob/main/docs/preprocess.md for more information.'
-		);
-		prependPreprocessors.push(createVitePreprocessorGroup(config));
-	}
-
 	// @ts-ignore
 	const pluginsWithPreprocessorsDeprecated = config.plugins.filter((p) => p?.sveltePreprocess);
 	if (pluginsWithPreprocessorsDeprecated.length > 0) {