src/vs/base/browser/ui/tree/indexTreeModel.ts/IndexTreeModel/hasTreeNode
class IndexTreeModel:	private hasTreeNode(location: number[], node: IIndexTreeNode<T, TFilterData> = this.root): boolean {
		if (!location || location.length === 0) {
			return true;
		}

		const [index, ...rest] = location;

		if (index < 0 || index > node.children.length) {
			return false;
		}

		return this.hasTreeNode(rest, node.children[index]);
	}