+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);
+
+export const activateNode = (id: string) => <T>(tree: Tree<T>) =>
+ mapTree((node: TreeNode<T>) => node.id === id ? { ...node, active: true } : { ...node, active: false })(tree);
+
+export const deactivateNode = <T>(tree: Tree<T>) =>
+ mapTree((node: TreeNode<T>) => node.active ? { ...node, active: false } : node)(tree);
+
+export const expandNode = (...ids: string[]) => <T>(tree: Tree<T>) =>
+ mapTree((node: TreeNode<T>) => ids.some(id => id === node.id) ? { ...node, expanded: true } : node)(tree);
+
+export const collapseNode = (...ids: string[]) => <T>(tree: Tree<T>) =>
+ mapTree((node: TreeNode<T>) => ids.some(id => id === node.id) ? { ...node, expanded: false } : node)(tree);
+
+export const toggleNodeCollapse = (...ids: string[]) => <T>(tree: Tree<T>) =>
+ mapTree((node: TreeNode<T>) => ids.some(id => id === node.id) ? { ...node, expanded: !node.expanded } : node)(tree);
+
+export const setNodeStatus = (id: string) => (status: TreeNodeStatus) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ return node
+ ? setNode({ ...node, status })(tree)
+ : tree;
+};
+
+export const toggleNodeSelection = (id: string) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ return node
+ ? pipe(
+ setNode({ ...node, selected: !node.selected }),
+ toggleAncestorsSelection(id),
+ toggleDescendantsSelection(id))(tree)
+ : tree;
+
+};
+
+export const selectNode = (id: string) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ return node && node.selected
+ ? tree
+ : toggleNodeSelection(id)(tree);
+};
+
+export const selectNodes = (id: string | string[]) => <T>(tree: Tree<T>) => {
+ const ids = typeof id === 'string' ? [id] : id;
+ return ids.reduce((tree, id) => selectNode(id)(tree), tree);
+};
+export const deselectNode = (id: string) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ return node && node.selected
+ ? toggleNodeSelection(id)(tree)
+ : tree;
+};
+
+export const deselectNodes = (id: string | string[]) => <T>(tree: Tree<T>) => {
+ const ids = typeof id === 'string' ? [id] : id;
+ return ids.reduce((tree, id) => deselectNode(id)(tree), tree);
+};
+
+export const getSelectedNodes = <T>(tree: Tree<T>) =>
+ getNodeDescendants('')(tree)
+ .filter(node => node.selected);
+
+export const initTreeNode = <T>(data: Pick<TreeNode<T>, 'id' | 'value'> & { parent?: string }): TreeNode<T> => ({
+ children: [],
+ active: false,
+ selected: false,
+ expanded: false,
+ status: TreeNodeStatus.INITIAL,
+ parent: '',
+ ...data,
+});
+
+const toggleDescendantsSelection = (id: string) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ if (node) {
+ return getNodeDescendants(id)(tree)
+ .reduce((newTree, subNode) =>
+ setNode({ ...subNode, selected: node.selected })(newTree),
+ tree);
+ }
+ return tree;
+};
+
+const toggleAncestorsSelection = (id: string) => <T>(tree: Tree<T>) => {
+ const ancestors = getNodeAncestorsIds(id)(tree).reverse();
+ return ancestors.reduce((newTree, parent) => parent ? toggleParentNodeSelection(parent)(newTree) : newTree, tree);
+};
+
+const toggleParentNodeSelection = (id: string) => <T>(tree: Tree<T>) => {
+ const node = getNode(id)(tree);
+ if (node) {
+ const parentNode = getNode(node.id)(tree);
+ if (parentNode) {
+ const selected = parentNode.children
+ .map(id => getNode(id)(tree))
+ .every(node => node !== undefined && node.selected);
+ return setNode({ ...parentNode, selected })(tree);
+ }
+ return setNode(node)(tree);
+ }
+ return tree;
+};
+