-export const getNodeChildren = (id: string) => <T>(tree: Tree<T>): string[] =>
- getNodeDescendants(id, 0)(tree);
+export const getNodeChildren = (id: string) => <T>(tree: Tree<T>) =>
+ mapIdsToNodes(getNodeChildrenIds(id)(tree))(tree);
+
+export const getNodeChildrenIds = (id: string) => <T>(tree: Tree<T>): string[] =>
+ getNodeDescendantsIds(id, 0)(tree);
+
+export const mapIdsToNodes = (ids: string[]) => <T>(tree: Tree<T>) =>
+ ids.map(id => getNode(id)(tree)).filter((node): node is TreeNode<T> => node !== undefined);