Allow folding of html blocks in markdown files

Fixes #57505

extensions/markdown-language-features/src/features/foldingProvider.ts

@@ -70,8 +70,19 @@ export default class MarkdownFoldingProvider implements vscode.FoldingRangeProvi
 
 	private async getBlockFoldingRanges(document: vscode.TextDocument): Promise<vscode.FoldingRange[]> {
 
-		const isFoldableToken = (token: Token) =>
-			['fence', 'list_item_open'].indexOf(token.type) >= 0 && token.map[1] > token.map[0];
+		const isFoldableToken = (token: Token) => {
+			switch (token.type) {
+				case 'fence':
+				case 'list_item_open':
+					return token.map[1] > token.map[0];
+
+				case 'html_block':
+					return token.map[1] > token.map[0] + 1;
+
+				default:
+					return false;
+			}
+		};
 
 		const tokens = await this.engine.parse(document.uri, document.getText());
 		const multiLineListItems = tokens.filter(isFoldableToken);

extensions/markdown-language-features/src/test/foldingProvider.test.ts

@@ -152,6 +152,17 @@ a`);
 		assert.strictEqual(firstFold.start, 4);
 		assert.strictEqual(firstFold.end, 6);
 	});
+
+	test('Should fold html blocks', async () => {
+		const folds = await getFoldsForDocument(`x
+<div>
+	fa
+</div>`);
+		assert.strictEqual(folds.length, 1);
+		const firstFold = folds[0];
+		assert.strictEqual(firstFold.start, 1);
+		assert.strictEqual(firstFold.end, 3);
+	});
 });