[folding] Support single shortcut for toggling fold/unfold. Fixes #18549

src/vs/editor/contrib/folding/folding.ts

@@ -14,7 +14,7 @@ import { ScrollType, IEditorContribution } from 'vs/editor/common/editorCommon';
 import { ITextModel } from 'vs/editor/common/model';
 import { registerEditorAction, registerEditorContribution, ServicesAccessor, EditorAction, registerInstantiatedEditorAction } from 'vs/editor/browser/editorExtensions';
 import { ICodeEditor, IEditorMouseEvent, MouseTargetType } from 'vs/editor/browser/editorBrowser';
-import { FoldingModel, setCollapseStateAtLevel, CollapseMemento, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines, setCollapseStateForType } from 'vs/editor/contrib/folding/foldingModel';
+import { FoldingModel, setCollapseStateAtLevel, CollapseMemento, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines, setCollapseStateForType, toggleCollapseState } from 'vs/editor/contrib/folding/foldingModel';
 import { FoldingDecorationProvider } from './foldingDecorations';
 import { FoldingRegions, FoldingRegion } from './foldingRanges';
 import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
@@ -656,6 +656,30 @@ class FoldAction extends FoldingAction<FoldingArguments> {
 	}
 }
 
+
+class ToggleFoldAction extends FoldingAction<void> {
+
+	constructor() {
+		super({
+			id: 'editor.toggleFold',
+			label: nls.localize('toggleFoldAction.label', "Toggle Fold"),
+			alias: 'Toggle Fold',
+			precondition: CONTEXT_FOLDING_ENABLED,
+			kbOpts: {
+				kbExpr: EditorContextKeys.editorTextFocus,
+				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_K),
+				weight: KeybindingWeight.EditorContrib
+			}
+		});
+	}
+
+	invoke(_foldingController: FoldingController, foldingModel: FoldingModel, editor: ICodeEditor): void {
+		let selectedLines = this.getSelectedLines(editor);
+		toggleCollapseState(foldingModel, 1, selectedLines);
+	}
+}
+
+
 class FoldRecursivelyAction extends FoldingAction<void> {
 
 	constructor() {
@@ -842,6 +866,7 @@ registerEditorAction(UnfoldAllAction);
 registerEditorAction(FoldAllBlockCommentsAction);
 registerEditorAction(FoldAllRegionsAction);
 registerEditorAction(UnfoldAllRegionsAction);
+registerEditorAction(ToggleFoldAction);
 
 for (let i = 1; i <= 7; i++) {
 	registerInstantiatedEditorAction(

src/vs/editor/contrib/folding/foldingModel.ts

@@ -242,6 +242,26 @@ export class FoldingModel {
 
 }
 
+/**
+ * Collapse or expand the regions at the given locations
+ * @param levels The number of levels. Use 1 to only impact the regions at the location, use Number.MAX_VALUE for all levels.
+ * @param lineNumbers the location of the regions to collapse or expand, or if not set, all regions in the model.
+ */
+export function toggleCollapseState(foldingModel: FoldingModel, levels: number, lineNumbers: number[]) {
+	let toToggle: FoldingRegion[] = [];
+	for (let lineNumber of lineNumbers) {
+		let region = foldingModel.getRegionAtLine(lineNumber);
+		if (region) {
+			const doCollapse = !region.isCollapsed;
+			toToggle.push(region);
+			if (levels > 1) {
+				let regionsInside = foldingModel.getRegionsInside(region, (r, level: number) => r.isCollapsed !== doCollapse && level < levels);
+				toToggle.push(...regionsInside);
+			}
+		}
+	}
+	foldingModel.toggleCollapseState(toToggle);
+}
 
 
 /**