tree: node.collapsible

src/vs/base/browser/ui/tree/tree.ts

@@ -63,6 +63,14 @@ interface ITreeListTemplateData<T> {
 	templateData: T;
 }
 
+function renderTwistie<T>(node: ITreeNode<T>, twistie: HTMLElement): void {
+	if (node.children.length === 0 && !node.collapsible) {
+		twistie.innerText = '';
+	} else {
+		twistie.innerText = node.collapsed ? '▹' : '◢';
+	}
+}
+
 class TreeRenderer<T, TTemplateData> implements IRenderer<ITreeNode<T>, ITreeListTemplateData<TTemplateData>> {
 
 	readonly templateId: string;
@@ -92,8 +100,8 @@ class TreeRenderer<T, TTemplateData> implements IRenderer<ITreeNode<T>, ITreeLis
 		this.renderedNodes.set(node, templateData);
 		templateData.elementDisposable = toDisposable(() => this.renderedNodes.delete(node));
 
-		templateData.twistie.innerText = node.children.length === 0 ? '' : (node.collapsed ? '▹' : '◢');
 		templateData.twistie.style.width = `${10 + node.depth * 10}px`;
+		renderTwistie(node, templateData.twistie);
 
 		this.renderer.renderElement(node.element, index, templateData.templateData);
 	}
@@ -109,7 +117,7 @@ class TreeRenderer<T, TTemplateData> implements IRenderer<ITreeNode<T>, ITreeLis
 			return;
 		}
 
-		templateData.twistie.innerText = node.children.length === 0 ? '' : (node.collapsed ? '▹' : '◢');
+		renderTwistie(node, templateData.twistie);
 	}
 
 	dispose(): void {

src/vs/base/browser/ui/tree/treeModel.ts

@@ -12,6 +12,7 @@ import { Emitter, Event } from 'vs/base/common/event';
 export interface ITreeElement<T> {
 	readonly element: T;
 	readonly children?: IIterator<ITreeElement<T>> | ITreeElement<T>[];
+	readonly collapsible?: boolean;
 	readonly collapsed?: boolean;
 }
 
@@ -20,6 +21,7 @@ export interface ITreeNode<T> {
 	readonly element: T;
 	readonly children: IMutableTreeNode<T>[];
 	readonly depth: number;
+	readonly collapsible: boolean;
 	readonly collapsed: boolean;
 	readonly visibleCount: number;
 }
@@ -61,8 +63,8 @@ function getTreeElementIterator<T>(elements: IIterator<ITreeElement<T>> | ITreeE
 
 function treeElementToNode<T>(treeElement: ITreeElement<T>, parent: IMutableTreeNode<T>, visible: boolean, treeListElements: ITreeNode<T>[]): IMutableTreeNode<T> {
 	const depth = parent.depth + 1;
-	const { element, collapsed } = treeElement;
-	const node = { parent, element, children: [], depth, collapsed: !!collapsed, visibleCount: 0 };
+	const { element, collapsible, collapsed } = treeElement;
+	const node = { parent, element, children: [], depth, collapsible: !!collapsible, collapsed: !!collapsed, visibleCount: 0 };
 
 	if (visible) {
 		treeListElements.push(node);
@@ -70,6 +72,7 @@ function treeElementToNode<T>(treeElement: ITreeElement<T>, parent: IMutableTree
 
 	const children = getTreeElementIterator(treeElement.children);
 	node.children = collect(map(children, el => treeElementToNode(el, node, visible && !treeElement.collapsed, treeListElements)));
+	node.collapsible = node.collapsible || node.children.length > 0;
 	node.visibleCount = 1 + getVisibleCount(node.children);
 
 	return node;
@@ -89,6 +92,7 @@ export class TreeModel<T> {
 		element: undefined,
 		children: [],
 		depth: 0,
+		collapsible: false,
 		collapsed: false,
 		visibleCount: 1
 	};
@@ -131,6 +135,10 @@ export class TreeModel<T> {
 	private _setCollapsed(location: number[], collapsed?: boolean | undefined): boolean {
 		const { node, listIndex, visible } = this.findNode(location);
 
+		if (!node.collapsible) {
+			return false;
+		}
+
 		if (typeof collapsed === 'undefined') {
 			collapsed = !node.collapsed;
 		}

test/tree/server.js

@@ -23,7 +23,7 @@ async function getTree(fsPath, level) {
 
 	const childNames = await fs.readdir(fsPath);
 	const children = await Promise.all(childNames.map(async childName => await getTree(path.join(fsPath, childName), level + 1)));
-	return { element, collapsed: false, children };
+	return { element, collapsible: true, collapsed: false, children };
 }
 
 app.use(serve('public'));