add markdown list folding, #57104 (#57899)

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

@@ -49,8 +49,8 @@ export default class MarkdownFoldingProvider implements vscode.FoldingRangeProvi
 		_: vscode.FoldingContext,
 		_token: vscode.CancellationToken
 	): Promise<vscode.FoldingRange[]> {
-		const [regions, sections] = await Promise.all([this.getRegions(document), this.getHeaderFoldingRanges(document)]);
-		return [...regions, ...sections].slice(0, rangeLimit);
+		const [regions, sections, lists] = await Promise.all([this.getRegions(document), this.getHeaderFoldingRanges(document), this.getListFoldingRanges(document)]);
+		return [...regions, ...sections, ...lists].slice(0, rangeLimit);
 	}
 
 	private async getHeaderFoldingRanges(document: vscode.TextDocument) {
@@ -64,4 +64,18 @@ export default class MarkdownFoldingProvider implements vscode.FoldingRangeProvi
 			return new vscode.FoldingRange(entry.line, endLine);
 		});
 	}
+
+	private async getListFoldingRanges(document: vscode.TextDocument): Promise<vscode.FoldingRange[]> {
+
+		const isMultiLineListOpen = (token: Token) =>
+			token.type === 'list_item_open' && token.map[1] > token.map[0];
+
+		const tokens = await this.engine.parse(document.uri, document.getText());
+		const multiLineListItems = tokens.filter(isMultiLineListOpen);
+		return multiLineListItems.map(listItem => {
+			const start = listItem.map[0];
+			const end = listItem.map[1] - 1;
+			return new vscode.FoldingRange(start, end);
+		});
+	}
 }

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

@@ -103,6 +103,25 @@ a`);
 		assert.strictEqual(second.end, 9);
 	});
 
+	test('Should fold from list to end of document', async () => {
+		const folds = await getFoldsForDocument(`a
+- b
+c
+d`);
+		assert.strictEqual(folds.length, 1);
+		const firstFold = folds[0];
+		assert.strictEqual(firstFold.start, 1);
+		assert.strictEqual(firstFold.end, 3);
+	});
+
+	test('Should fold if list has multiple lines of content', async () => {
+		const folds = await getFoldsForDocument(`a
+- This list item\n  spans multiple\n  lines.`);
+		assert.strictEqual(folds.length, 1);
+		const firstFold = folds[0];
+		assert.strictEqual(firstFold.start, 1);
+		assert.strictEqual(firstFold.end, 3);
+	});
 });