fix: allow to init the highlighter without themes and langs

Author: antfu

packages/shikiji/src/core/core.ts

@@ -9,7 +9,7 @@ import { renderToHtmlDualThemes } from './renderer-html-dual-themes'
 
 export type HighlighterCore = HighlighterGeneric<never, never>
 
-export async function getHighlighterCore(options: HighlighterCoreOptions): Promise<HighlighterCore> {
+export async function getHighlighterCore(options: HighlighterCoreOptions = {}): Promise<HighlighterCore> {
   async function resolveLangs(langs: LanguageInput[]) {
     return Array.from(new Set((await Promise.all(
       langs.map(async lang => await normalizeGetter(lang).then(r => Array.isArray(r) ? r : [r])),
@@ -19,8 +19,8 @@ export async function getHighlighterCore(options: HighlighterCoreOptions): Promi
   const [
     themes, langs,
   ] = await Promise.all([
-    Promise.all(options.themes.map(normalizeGetter)),
-    resolveLangs(options.langs),
+    Promise.all((options.themes || []).map(normalizeGetter)),
+    resolveLangs(options.langs || []),
     typeof options.loadWasm === 'function'
       ? Promise.resolve(options.loadWasm()).then(r => loadWasm(r))
       : options.loadWasm
@@ -40,7 +40,7 @@ export async function getHighlighterCore(options: HighlighterCoreOptions): Promi
   const _registry = new Registry(resolver, themes, langs)
   await _registry.init()
 
-  const defaultTheme = themes[0].name
+  const defaultTheme = themes[0]?.name
 
   function codeToThemedTokens(
     code: string,

packages/shikiji/src/types.ts

@@ -49,8 +49,8 @@ export interface HighlighterGeneric<BundledLangKeys extends string, BundledTheme
 }
 
 export interface HighlighterCoreOptions {
-  themes: ThemeInput[]
-  langs: LanguageInput[]
+  themes?: ThemeInput[]
+  langs?: LanguageInput[]
   loadWasm?: OnigurumaLoadOptions | (() => Promise<OnigurumaLoadOptions>)
 }
 

packages/shikiji/test/core.test.ts

@@ -76,6 +76,17 @@ describe('should', () => {
         ]
       `)
   })
+
+  it('works without no initial langs and themes', async () => {
+    const shiki = await getHighlighterCore()
+
+    await shiki.loadLanguage(js)
+    await shiki.loadTheme(nord)
+
+    const code = shiki.codeToHtml('console.log("Hi")', { lang: 'javascript', theme: 'nord' })
+
+    expect(code).toMatchInlineSnapshot('"<pre class=\\"shiki nord\\" style=\\"background-color:#2e3440ff;color:#2e3440ff\\" tabindex=\\"0\\"><code><span class=\\"line\\"><span style=\\"color:#D8DEE9\\">console</span><span style=\\"color:#ECEFF4\\">.</span><span style=\\"color:#88C0D0\\">log</span><span style=\\"color:#D8DEE9FF\\">(</span><span style=\\"color:#ECEFF4\\">&quot;</span><span style=\\"color:#A3BE8C\\">Hi</span><span style=\\"color:#ECEFF4\\">&quot;</span><span style=\\"color:#D8DEE9FF\\">)</span></span></code></pre>"')
+  })
 })
 
 describe('errors', () => {