+export const mapTreeValues = <T, R>(mapFn: (value: T) => R) => (tree: Tree<T>): Tree<R> =>
+ getNodeDescendants('')(tree)
+ .map(id => getNode(id)(tree))
+ .map(mapNodeValue(mapFn))
+ .reduce((newTree, node) => setNode(node)(newTree), createTree<R>());
+
+export const mapTree = <T, R>(mapFn: (node: TreeNode<T>) => TreeNode<R>) => (tree: Tree<T>): Tree<R> =>
+ getNodeDescendants('')(tree)
+ .map(id => getNode(id)(tree))
+ .map(mapFn)
+ .reduce((newTree, node) => setNode(node)(newTree), createTree<R>());