Function loadGrammarsForLanguages

src/extraction/grammars.ts:189–235

(languages: Language[])

 * Must be called after initGrammars().
 */
export async function loadGrammarsForLanguages(languages: Language[]): Promise<void> {
  if (!parserInitialized) {
    await initGrammars();
  }

  // SFC languages (svelte/vue/astro) have no grammar of their own — their
  // extractors delegate <script>/frontmatter content to the TS/JS extractor,
  // so those grammars must be loaded even when no plain .ts/.js file is in
  // the index set (e.g. a pure-.astro content site).
  if (languages.some((l) => l === 'svelte' || l === 'vue' || l === 'astro')) {
    languages = [...languages, 'typescript', 'javascript'];
  }

  // Deduplicate and filter to languages that have WASM grammars and aren't already loaded
  const toLoad = [...new Set(languages)].filter(
    (lang): lang is GrammarLanguage =>
      lang in WASM_GRAMMAR_FILES &&
      !languageCache.has(lang) &&
      !unavailableGrammarErrors.has(lang)
  );

  // Load grammars sequentially to avoid web-tree-sitter WASM race condition on Node 20+
  // See: https://github.com/tree-sitter/tree-sitter/issues/2338
  for (const lang of toLoad) {
    const wasmFile = WASM_GRAMMAR_FILES[lang];
    try {
      // Some grammars ship their own WASMs (not in tree-sitter-wasms, or the
      // tree-sitter-wasms build is too old). Lua: tree-sitter-wasms ships an
      // ABI-13 build that corrupts the shared WASM heap under web-tree-sitter
      // 0.25 (drops nested calls/imports on every file after the first); we
      // vendor the upstream ABI-15 wasm instead. C#: the tree-sitter-wasms
      // build (ABI 13) has no primary-constructor support and parses
      // `class Foo(...)` as an ERROR that swallows the whole class (#237); we
      // vendor the upstream ABI-15 tree-sitter-c-sharp 0.23.5 wasm, which parses
      // primary constructors natively.
      const wasmPath = (lang === 'pascal' || lang === 'scala' || lang === 'lua' || lang === 'luau' || lang === 'csharp' || lang === 'r')
        ? path.join(__dirname, 'wasm', wasmFile)
        : require.resolve(`tree-sitter-wasms/out/${wasmFile}`);
      const language = await WasmLanguage.load(wasmPath);
      languageCache.set(lang, language);
    } catch (error) {
      const message = error instanceof Error ? error.message : String(error);
      console.warn(`[CodeGraph] Failed to load ${lang} grammar — parsing will be unavailable: ${message}`);
      unavailableGrammarErrors.set(lang, message);
    }
  }
}

/**
 * Load ALL grammar WASM files. Convenience function for tests and