{
  "url": "https://unifast.dev/ja/docs/packages/core/extract-lang/",
  "locale": "ja",
  "title": "extractLang()",
  "description": "code 要素の className からプログラミング言語を抽出します。",
  "section": "packages",
  "body": "```ts\nimport { extractLang } from \"@unifast/core\";\n```\n\n## シグネチャ\n\n```ts\nfunction extractLang(code: HastElement): string | null\n```\n\n## パラメータ\n\n### code\n\n| プロパティ | 型 | デフォルト | 説明 |\n|----------|------|---------|-------------|\n| `type` | `\"element\"` | — | ノード種別の識別子 |\n| `tagName` | `string` | — | HTML のタグ名 (通常は `\"code\"`) |\n| `properties` | `Record<string, unknown>` | — | `className` を含む要素のプロパティ |\n| `children` | `HastNode[]` | — | 要素の子ノード |\n\n## 戻り値\n\n`string | null` — 最初の `language-*` クラスから抽出された言語識別子です。言語クラスが見つからない場合は `null` を返します。\n\n## 使い方\n\n```ts\nimport { extractLang } from \"@unifast/core\";\nimport type { HastElement } from \"@unifast/core\";\n\nconst codeElement: HastElement = {\n  type: \"element\",\n  tagName: \"code\",\n  properties: { className: [\"language-typescript\"] },\n  children: [{ type: \"text\", value: \"const x = 1;\" }],\n};\n\nconst lang = extractLang(codeElement);\n\nconsole.log(lang);\n// typescript\n```\n\n## 使用例\n\n### code 要素から言語を抽出する\n\n```ts\nimport { extractLang } from \"@unifast/core\";\nimport type { HastElement } from \"@unifast/core\";\n\nconst code: HastElement = {\n  type: \"element\",\n  tagName: \"code\",\n  properties: { className: [\"language-js\", \"highlight\"] },\n  children: [{ type: \"text\", value: \"console.log('hello');\" }],\n};\n\nconsole.log(extractLang(code));\n// js\n```\n\n### 言語クラスがない場合\n\n```ts\nimport { extractLang } from \"@unifast/core\";\nimport type { HastElement } from \"@unifast/core\";\n\nconst code: HastElement = {\n  type: \"element\",\n  tagName: \"code\",\n  properties: { className: [\"highlight\"] },\n  children: [{ type: \"text\", value: \"plain text\" }],\n};\n\nconsole.log(extractLang(code));\n// null\n```\n\n### className が配列でない場合\n\n```ts\nimport { extractLang } from \"@unifast/core\";\nimport type { HastElement } from \"@unifast/core\";\n\nconst code: HastElement = {\n  type: \"element\",\n  tagName: \"code\",\n  properties: {},\n  children: [{ type: \"text\", value: \"no classes\" }],\n};\n\nconsole.log(extractLang(code));\n// null\n```\n\n### findCodeChild と組み合わせて使う\n\n```ts\nimport { extractLang, findCodeChild } from \"@unifast/core\";\nimport type { HastElement } from \"@unifast/core\";\n\nconst pre: HastElement = {\n  type: \"element\",\n  tagName: \"pre\",\n  properties: {},\n  children: [\n    {\n      type: \"element\",\n      tagName: \"code\",\n      properties: { className: [\"language-python\"] },\n      children: [{ type: \"text\", value: \"print('hello')\" }],\n    },\n  ],\n};\n\nconst code = findCodeChild(pre);\nif (code) {\n  console.log(extractLang(code));\n  // python\n}\n```",
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      "locale": "ru",
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      "locale": "hi",
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}