docs(vitePreprocess): ts is no longer preprocessed by default (#974)

* docs(vitePreprocess): change wording to show that script is no longer preprocessed by default

* docs(vitePreprocess): more details around new script default

* Apply suggestions from code review

Co-authored-by: Simon H <[email protected]>

---------

Co-authored-by: Simon H <[email protected]>

Author: dominikg

docs/preprocess.md

@@ -2,14 +2,14 @@
 
 `vite-plugin-svelte` also exports Vite preprocessors to preprocess Svelte components using Vite's built-in transformers.
 
-Compared to [`svelte-preprocess`](https://github.com/sveltejs/svelte-preprocess), Vite preprocessors share the same CSS configuration from the Vite config so you don't have to configure them twice. [`esbuild`](http://esbuild.github.io) is also used to transform TypeScript by default.
+Compared to [`svelte-preprocess`](https://github.com/sveltejs/svelte-preprocess), Vite preprocessors share the same CSS configuration from the Vite config so you don't have to configure them twice. [`esbuild`](http://esbuild.github.io) can also be used to transform TypeScript.
 
 However, `svelte-preprocess` does provide extra functionalities not available with Vite preprocessors, such as [template tag](https://github.com/sveltejs/svelte-preprocess#template-tag), [external files](https://github.com/sveltejs/svelte-preprocess#external-files), and [global styles](https://github.com/sveltejs/svelte-preprocess#global-style) ([though it's recommended to use import instead](./faq.md#where-should-i-put-my-global-styles)). If those features are required, you can still use `svelte-preprocess`, but make sure to turn off it's script and style preprocessing options.
 
 ## vitePreprocess
 
 - **Type:** `{ script?: boolean, style?: boolean | InlineConfig | ResolvedConfig }`
-- **Default:** `{ script: true, style: true }`
+- **Default:** `{ script: false, style: true }`
 
   A Svelte preprocessor that supports transforming TypeScript, PostCSS, SCSS, Less, Stylus, and SugarSS. These are transformed when the script or style tags have the respective `lang` attribute.
 
@@ -20,16 +20,29 @@ However, `svelte-preprocess` does provide extra functionalities not available wi
   - SugarSS: `<style lang="sss">`
 
   By default, PostCSS or LightningCSS ([if configured in Vite](https://vitejs.dev/config/shared-options.html#css-transformer)) is applied to all `<style>` tags.
+  If required, you can turn transforming off by setting the `style` option to `false`. The `style` option also accepts Vite's `InlineConfig` and `ResolvedConfig` types for advanced usage.
 
-  If required, you can turn script or style transforming off by setting the `script` or `style` option to `false`. The `style` option also accepts Vite's `InlineConfig` and `ResolvedConfig` types for advanced usage.
+TypeScript is no longer preprocessed by default as Svelte 5 understands most syntax natively.
+If you use TypeScript features that emit code (like `enum`, `using`, `accessors`, decorators or class declarations with visibility modifiers), you have to enable the script preprocessor by setting the `script` option to `true`.
 
-  **Example:**
+### Examples
 
-  ```js
-  // svelte.config.js
-  import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+#### default
 
-  export default {
-    preprocess: [vitePreprocess()]
-  };
-  ```
+```js
+// svelte.config.js
+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+export default {
+  preprocess: [vitePreprocess()]
+};
+```
+
+#### enable script preprocessing for advanced TypeScript syntax use
+
+```js
+// svelte.config.js
+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+export default {
+  preprocess: [vitePreprocess({ script: true })]
+};
+```