fix: resolve comment end confusion inside inline JavaScript (#151)

src/htmlLanguageService.ts

@@ -87,6 +87,8 @@ export function getLanguageService(options: LanguageServiceOptions = defaultLang
 	};
 }
 
+export { convertScriptContentToJavaScript } from './parser/htmlScanner.js';
+
 export function newHTMLDataProvider(id: string, customData: HTMLDataV1): IHTMLDataProvider {
 	return new HTMLDataProvider(id, customData);
 }

src/parser/htmlScanner.ts

@@ -429,3 +429,26 @@ export function createScanner(input: string, initialOffset = 0, initialState: Sc
 		getTokenError: () => tokenError
 	};
 }
+
+/**
+ * Converts HTML comment markers (`<!--` and `-->`) in inline script content
+ * to JavaScript block comment markers (`/* ` and ` *​/`), only replacing
+ * matched pairs. Unpaired `-->` (e.g., inside a JS block comment like
+ * `/* --> *​/`) will not be replaced.
+ */
+export function convertScriptContentToJavaScript(content: string): string {
+	const re = /<!--|-->/g;
+	let depth = 0;
+	return content.replace(re, (match) => {
+		if (match === '<!--') {
+			depth++;
+			return '/* ';
+		}
+		// match === '-->'
+		if (depth > 0) {
+			depth--;
+			return ' */';
+		}
+		return match;
+	});
+}

src/test/scanner.test.ts

@@ -5,7 +5,7 @@
 
 import { suite, test } from 'node:test';
 import * as assert from 'node:assert';
-import { createScanner } from '../parser/htmlScanner.js';
+import { createScanner, convertScriptContentToJavaScript } from '../parser/htmlScanner.js';
 import { TokenType, ScannerState } from '../htmlLanguageTypes.js';
 
 suite('HTML Scanner', () => {
@@ -876,4 +876,66 @@ suite('HTML Scanner', () => {
 		]);
 	});
 
+});
+
+suite('convertScriptContentToJavaScript', () => {
+
+	test('replaces matched <!-- and --> pairs', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript('<!-- var x = 1; -->'),
+			'/*  var x = 1;  */'
+		);
+	});
+
+	test('does not replace unpaired -->', () => {
+		// Issue #151: --> inside a JS block comment should not be replaced
+		assert.strictEqual(
+			convertScriptContentToJavaScript('/* --> a b\n  */'),
+			'/* --> a b\n  */'
+		);
+	});
+
+	test('replaces only paired markers when mixed', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript('<!-- code --> /* --> */'),
+			'/*  code  */ /* --> */'
+		);
+	});
+
+	test('handles multiple pairs', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript('<!-- a --> <!-- b -->'),
+			'/*  a  */ /*  b  */'
+		);
+	});
+
+	test('handles nested <!-- inside already open comment', () => {
+		// Second <!-- is also replaced since depth tracking allows it
+		assert.strictEqual(
+			convertScriptContentToJavaScript('<!-- <!-- --> -->'),
+			'/*  /*   */  */'
+		);
+	});
+
+	test('handles empty script content', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript(''),
+			''
+		);
+	});
+
+	test('handles content with no markers', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript('var x = 1;'),
+			'var x = 1;'
+		);
+	});
+
+	test('leaves unpaired <!-- without replacement of -->', () => {
+		assert.strictEqual(
+			convertScriptContentToJavaScript('<!-- var x = 1;'),
+			'/*  var x = 1;'
+		);
+	});
+
 });