feat(rehype): add langAlias option (#1015)

Author: SoonIter

packages/rehype/src/index.ts

@@ -16,13 +16,19 @@ export type RehypeShikiOptions = RehypeShikiCoreOptions
      * @default Object.keys(bundledLanguages)
      */
     langs?: Array<LanguageInput | BuiltinLanguage>
+    /**
+     * Alias of languages
+     * @example { 'my-lang': 'javascript' }
+     */
+    langAlias?: Record<string, string>
   }
 
 const rehypeShiki: Plugin<[RehypeShikiOptions], Root> = function (
   options = {} as RehypeShikiOptions,
 ) {
   const themeNames = ('themes' in options ? Object.values(options.themes) : [options.theme]).filter(Boolean) as BuiltinTheme[]
   const langs = options.langs || Object.keys(bundledLanguages)
+  const langAlias = options.langAlias || {}
 
   let getHandler: Promise<any>
 
@@ -31,6 +37,7 @@ const rehypeShiki: Plugin<[RehypeShikiOptions], Root> = function (
       getHandler = getSingletonHighlighter({
         themes: themeNames,
         langs,
+        langAlias,
       })
         .then(highlighter => rehypeShikiFromHighlighter.call(this, highlighter, options))
     }

packages/rehype/test/fixtures/lang-alias.md

@@ -7,6 +7,24 @@ import { unified } from 'unified'
 import { expect, it } from 'vitest'
 import rehypeShiki from '../src'
 
+it('lang-alias', async () => {
+  const file = await unified()
+    .use(remarkParse)
+    .use(remarkRehype)
+    .use(rehypeShiki, {
+      theme: 'vitesse-light',
+      addLanguageClass: true,
+      langAlias: {
+        mylang: 'javascript',
+        mylang2: 'js', // nested alias
+      },
+    })
+    .use(rehypeStringify)
+    .process(await fs.readFile(new URL('./fixtures/lang-alias.md', import.meta.url)))
+
+  await expect(file.toString()).toMatchFileSnapshot('./fixtures/lang-alias.out.html')
+})
+
 it('run', async () => {
   const file = await unified()
     .use(remarkParse)