feat(wasm): add Language.loadSync for synchronous loading

lib/binding_web/test/language.test.ts

@@ -1,13 +1,37 @@
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
-import helper from './helper';
-import type { LookaheadIterator, Language } from '../src';
+import helper, { type LanguageName } from './helper';
+import { LookaheadIterator, Language } from '../src';
 import { Parser } from '../src';
+import { readFile } from 'fs/promises';
 
 let JavaScript: Language;
 let Rust: Language;
+let languageURL: (name: LanguageName) => string;
 
 describe('Language', () => {
-  beforeAll(async () => ({ JavaScript, Rust } = await helper));
+  beforeAll(async () => ({ JavaScript, Rust, languageURL } = await helper));
+
+  describe('.loadSync', () => {
+    it('loads a language synchronously from a pre-compiled WebAssembly.Module', async () => {
+      const wasmPath = languageURL('javascript');
+      const wasmBytes = await readFile(wasmPath);
+      const wasmModule = await WebAssembly.compile(wasmBytes);
+
+      const lang = Language.loadSync(wasmModule);
+      expect(lang.name).toBe('javascript');
+      expect(lang.abiVersion).toBe(15);
+
+      // Verify the language actually works by parsing a snippet
+      const parser = new Parser();
+      parser.setLanguage(lang);
+      const tree = parser.parse('const x = 1;');
+      expect(tree).not.toBeNull();
+      expect(tree!.rootNode.type).toBe('program');
+      expect(tree!.rootNode.childCount).toBe(1);
+      expect(tree!.rootNode.firstChild!.type).toBe('lexical_declaration');
+      parser.delete();
+    });
+  });
 
   describe('.name, .version', () => {
     it('returns the name and version of the language', () => {