feat(css): add preprocessor option to define stylus vars & funcs

docs/config/shared-options.md

@@ -226,7 +226,15 @@ Note if an inline config is provided, Vite will not search for other PostCSS con
 
 - **Type:** `Record<string, object>`
 
-Specify options to pass to CSS pre-processors. The file extensions are used as keys for the options. Example:
+Specify options to pass to CSS pre-processors. The file extensions are used as keys for the options. The supported options for each preprocessors can be found in their respective documentation:
+
+- `sass`/`scss` - [Options](https://sass-lang.com/documentation/js-api/interfaces/LegacyStringOptions).
+- `less` - [Options](https://lesscss.org/usage/#less-options).
+- `styl`/`stylus` - Only [`define`](https://stylus-lang.com/docs/js.html#define-name-node) is supported, which can be passed as an object.
+
+All preprocessor options also support the `additionalData` option, which can be used to inject extra code for each style content.
+
+Example:
 
 ```js
 export default defineConfig({
@@ -235,8 +243,13 @@ export default defineConfig({
       scss: {
         additionalData: `$injectedColor: orange;`,
       },
+      less: {
+        math: 'parens-division',
+      },
       styl: {
-        additionalData: `$injectedColor ?= orange`,
+        define: {
+          $specialColor: new stylus.Parser('#33C5FF').peek().val,
+        },
       },
     },
   },

packages/vite/src/node/plugins/css.ts

@@ -1453,6 +1453,10 @@ type StylePreprocessorOptions = {
 
 type SassStylePreprocessorOptions = StylePreprocessorOptions & Sass.Options
 
+type StylusStylePreprocessorOptions = StylePreprocessorOptions & {
+  define?: Record<string, any>
+}
+
 type StylePreprocessor = (
   source: string,
   root: string,
@@ -1467,6 +1471,13 @@ type SassStylePreprocessor = (
   resolvers: CSSAtImportResolvers,
 ) => StylePreprocessorResults | Promise<StylePreprocessorResults>
 
+type StylusStylePreprocessor = (
+  source: string,
+  root: string,
+  options: StylusStylePreprocessorOptions,
+  resolvers: CSSAtImportResolvers,
+) => StylePreprocessorResults | Promise<StylePreprocessorResults>
+
 export interface StylePreprocessorResults {
   code: string
   map?: ExistingRawSourceMap | undefined
@@ -1847,7 +1858,7 @@ function createViteLessPlugin(
 }
 
 // .styl
-const styl: StylePreprocessor = async (source, root, options) => {
+const styl: StylusStylePreprocessor = async (source, root, options) => {
   const nodeStylus = loadPreprocessor(PreprocessLang.stylus, root)
   // Get source with preprocessor options.additionalData. Make sure a new line separator
   // is added to avoid any render error, as added stylus content may not have semi-colon separators
@@ -1865,6 +1876,11 @@ const styl: StylePreprocessor = async (source, root, options) => {
   )
   try {
     const ref = nodeStylus(content, options)
+    if (options.define) {
+      for (const key in options.define) {
+        ref.define(key, options.define[key])
+      }
+    }
     if (options.enableSourcemap) {
       ref.set('sourcemap', {
         comment: false,

playground/css/__tests__/css.spec.ts

@@ -146,6 +146,8 @@ test('stylus', async () => {
   const relativeImportAlias = await page.$('.stylus-import-alias')
   const optionsRelativeImport = await page.$('.stylus-options-relative-import')
   const optionsAbsoluteImport = await page.$('.stylus-options-absolute-import')
+  const optionsDefineVar = await page.$('.stylus-options-define-var')
+  const optionsDefineFunc = await page.$('.stylus-options-define-func')
 
   expect(await getColor(imported)).toBe('blue')
   expect(await getColor(additionalData)).toBe('orange')
@@ -156,6 +158,8 @@ test('stylus', async () => {
   )
   expect(await getColor(optionsRelativeImport)).toBe('green')
   expect(await getColor(optionsAbsoluteImport)).toBe('red')
+  expect(await getColor(optionsDefineVar)).toBe('rgb(51, 197, 255)')
+  expect(await getColor(optionsDefineFunc)).toBe('rgb(255, 0, 98)')
 
   editFile('stylus.styl', (code) =>
     code.replace('$color ?= blue', '$color ?= red'),

playground/css/index.html

@@ -72,6 +72,14 @@ <h1>CSS</h1>
     Stylus import (absolute path) via vite config preprocessor options: This
     should be red
   </p>
+  <p class="stylus-options-define-var">
+    Stylus define variable via vite config preprocessor options: This should be
+    rgb(51, 197, 255)
+  </p>
+  <p class="stylus-options-define-func">
+    Stylus define function via vite config preprocessor options: This should be
+    rgb(255, 0, 98)
+  </p>
   <p>Imported Stylus string:</p>
   <pre class="imported-stylus"></pre>
 

playground/css/stylus.styl

@@ -8,3 +8,11 @@ $color ?= blue
 .stylus-additional-data
   /* injected via vite.config.js */
   color $injectedColor
+
+.stylus-options-define-var
+  /* defined in vite.config.js */
+  color $definedColor
+
+.stylus-options-define-func
+  /* defined in vite.config.js */
+  color definedFunction()

playground/css/vite.config.js

@@ -1,4 +1,5 @@
 import path from 'node:path'
+import stylus from 'stylus'
 import { defineConfig } from 'vite'
 
 // trigger scss bug: https://github.com/sass/dart-sass/issues/710
@@ -68,6 +69,10 @@ export default defineConfig({
           './options/relative-import.styl',
           path.join(__dirname, 'options/absolute-import.styl'),
         ],
+        define: {
+          $definedColor: new stylus.Parser('#33C5FF').peek().val,
+          definedFunction: () => new stylus.nodes.RGBA(255, 0, 98, 1),
+        },
       },
     },
   },