fix(core): allow langAlias to special languages, close #1164

Author: antfu

packages/core/src/constructors/_alias.ts

@@ -0,0 +1,16 @@
+import { ShikiError } from '../../../types/src/error'
+
+export function resolveLangAlias(name: string, alias?: Record<string, string>): string {
+  if (!alias)
+    return name
+  if (alias[name]) {
+    const resolved = new Set<string>([name])
+    while (alias[name]) {
+      name = alias[name]
+      if (resolved.has(name))
+        throw new ShikiError(`Circular alias \`${Array.from(resolved).join(' -> ')} -> ${name}\``)
+      resolved.add(name)
+    }
+  }
+  return name
+}

packages/core/src/constructors/bundle-factory.ts

@@ -62,9 +62,9 @@ export function createBundledHighlighter<BundledLangs extends string, BundledThe
   ): Promise<HighlighterGeneric<BundledLangs, BundledThemes>> {
     function resolveLang(lang: LanguageInput | BundledLangs | SpecialLanguage): LanguageInput {
       if (typeof lang === 'string') {
+        lang = (options.langAlias?.[lang] || lang) as LanguageInput | BundledLangs | SpecialLanguage
         if (isSpecialLang(lang))
           return []
-        lang = (options.langAlias?.[lang] || lang) as LanguageInput | BundledLangs | SpecialLanguage
         const bundle = bundledLanguages[lang as BundledLangs]
         if (!bundle)
           throw new ShikiError(`Language \`${lang}\` is not included in this bundle. You may want to load it from external source.`)

packages/core/src/constructors/internal-sync.ts

@@ -11,12 +11,12 @@ import type {
   ThemeRegistrationAny,
   ThemeRegistrationResolved,
 } from '@shikijs/types'
-
 import { ShikiError } from '../../../types/src/error'
 import { resolveLangs, resolveThemes } from '../textmate/getters-resolve'
 import { normalizeTheme } from '../textmate/normalize-theme'
 import { Registry } from '../textmate/registry'
 import { Resolver } from '../textmate/resolver'
+import { resolveLangAlias as _resolveLangAlias } from './_alias'
 
 let instancesCount = 0
 
@@ -43,6 +43,10 @@ export function createShikiInternalSync(options: HighlighterCoreOptions<true>):
 
   let _lastTheme: string | ThemeRegistrationAny
 
+  function resolveLangAlias(name: string): string {
+    return _resolveLangAlias(name, options.langAlias)
+  }
+
   function getLanguage(name: string | LanguageRegistration): Grammar {
     ensureNotDisposed()
     const _lang = _registry.getGrammar(typeof name === 'string' ? name : name.name)
@@ -128,6 +132,7 @@ export function createShikiInternalSync(options: HighlighterCoreOptions<true>):
     getLanguage,
     getLoadedThemes,
     getLoadedLanguages,
+    resolveLangAlias,
     loadLanguage,
     loadLanguageSync,
     loadTheme,

packages/core/src/highlight/code-to-tokens-base.ts

@@ -34,10 +34,11 @@ export function codeToTokensBase(
   options: CodeToTokensBaseOptions = {},
 ): ThemedToken[][] {
   const {
-    lang = 'text',
     theme: themeName = internal.getLoadedThemes()[0],
   } = options
 
+  const lang = internal.resolveLangAlias(options.lang || 'text')
+
   if (isPlainLang(lang) || isNoneTheme(themeName))
     return splitLines(code).map(line => [{ content: line[0], offset: line[1] }])
 
@@ -46,7 +47,7 @@ export function codeToTokensBase(
   if (lang === 'ansi')
     return tokenizeAnsiWithTheme(theme, code, options)
 
-  const _grammar = internal.getLanguage(lang)
+  const _grammar = internal.getLanguage(options.lang || 'text')
 
   if (options.grammarState) {
     if (options.grammarState.lang !== _grammar.name) {

packages/core/src/textmate/registry.ts

@@ -8,6 +8,7 @@ import type { IGrammarConfiguration, IRawTheme } from '@shikijs/vscode-textmate'
 import type { Resolver } from './resolver'
 import { Registry as TextMateRegistry, Theme as TextMateTheme } from '@shikijs/vscode-textmate'
 import { ShikiError } from '../../../types/src/error'
+import { resolveLangAlias } from '../constructors/_alias'
 import { normalizeTheme } from './normalize-theme'
 
 export class Registry extends TextMateRegistry {
@@ -71,15 +72,7 @@ export class Registry extends TextMateRegistry {
   }
 
   public getGrammar(name: string): Grammar | undefined {
-    if (this._alias[name]) {
-      const resolved = new Set<string>([name])
-      while (this._alias[name]) {
-        name = this._alias[name]
-        if (resolved.has(name))
-          throw new ShikiError(`Circular alias \`${Array.from(resolved).join(' -> ')} -> ${name}\``)
-        resolved.add(name)
-      }
-    }
+    name = resolveLangAlias(name, this._alias)
     return this._resolvedGrammars.get(name)
   }
 

packages/core/test/core.test.ts

@@ -132,6 +132,34 @@ describe('should', () => {
     const code = shiki.codeToHtml('const a: Foo = 1', { lang: 'js', theme: 'nord' })
     expect(code).toMatchInlineSnapshot(`"<pre class="shiki nord" style="background-color:#2e3440ff;color:#d8dee9ff" tabindex="0"><code><span class="line"><span style="color:#81A1C1">const</span><span style="color:#D8DEE9"> a</span><span style="color:#81A1C1">:</span><span style="color:#8FBCBB"> Foo</span><span style="color:#81A1C1"> =</span><span style="color:#B48EAD"> 1</span></span></code></pre>"`)
   })
+
+  it('works with alias and special langs', async () => {
+    using shiki = await createHighlighterCore({
+      langAlias: {
+        lang1: 'text',
+        lang2: 'ansi',
+        lang3: 'lang4',
+        lang4: 'lang5',
+        lang5: 'ansi',
+      },
+      engine: createJavaScriptRegexEngine(),
+    })
+
+    await shiki.loadTheme(nord)
+
+    const original1 = shiki.codeToHtml('console.log("Hi")', { lang: 'text', theme: 'nord' })
+    const code1 = shiki.codeToHtml('console.log("Hi")', { lang: 'lang1', theme: 'nord' })
+    expect(code1).toBe(original1)
+
+    const ansiCode = 'colored foregroundcolored backgroundbold textdimmed textunderlined textreversed textstrikethrough textunderlined + strikethrough text'
+    const original2 = shiki.codeToHtml(ansiCode, { lang: 'ansi', theme: 'nord' })
+    const code2 = shiki.codeToHtml(ansiCode, { lang: 'lang2', theme: 'nord' })
+    expect(code2).toBe(original2)
+
+    // nested alias
+    const code3 = shiki.codeToHtml(ansiCode, { lang: 'lang3', theme: 'nord' })
+    expect(code3).toBe(original2)
+  })
 })
 
 describe('errors', () => {

packages/types/src/highlighter.ts

@@ -60,6 +60,10 @@ export interface ShikiInternal<BundledLangKeys extends string = never, BundledTh
     colorMap: string[]
   }
 
+  /**
+   * Resolve a language alias
+   */
+  resolveLangAlias: (lang: string) => string
   /**
    * Get the names of loaded languages
    *