Tree

A lightweight JavaScript library for tree data structure operations.

Installation

npm i @axolo/tree

Usage

import Tree from '@axolo/tree'

// Sample data
const array = [
  { id: 1, parentId: null, name: 'Root' },
  { id: 2, parentId: 1, name: 'Child 1' },
  { id: 3, parentId: 1, name: 'Child 2' },
  { id: 4, parentId: 2, name: 'Grandchild' }
]

// Convert array to tree
const tree = Tree.from(array)

// Convert tree to array
const resultArray = tree.toArray()

// Get path by id
const path = tree.path(4) // [{ id: 1, ... }, { id: 2, ... }, { id: 4, ... }]
const pathIds = tree.path(4, 'id') // [1, 2, 4]
const pathIndices = tree.path(4, null) // [0, 0, 0]

// Get parent node
const parent = tree.parent(4) // { id: 2, ... }

// Filter tree
const filtered = tree.filter(node => node.name.includes('Child'))

// Get subtree
const subtree = tree.sub(2) // [{ id: 2, children: [...] }]

// Get tree depth
const depth = tree.getDepth() // 3

Configuration

Property	Type	Default	Description
id	string	'id'	Unique identifier property name
parentId	string	'parentId'	Parent node identifier property name
children	string	'children'	Children property name
depth	string	'depth'	Depth property name
leaf	string	'leaf'	Leaf node flag property name

API

Tree.from(array, config = {})

Convert an array to a tree structure.

Parameters:

• array {Array} - Array representation of tree data
• config {Object} - Optional configuration object

Returns: {Tree} - Tree instance

tree.toArray()

Convert tree back to array.

Returns: {Array} - Array representation of the tree

tree.path(id, key = undefined)

Get the path from root to the target node.

Parameters:

• id {String|Number} - Target node id
• key {String|null|undefined} - Return property key

Returns: {Array} Path array containing nodes, specified keys, or indices depending on key parameter

• key is undefined: nodes like [root, ..., parent, self]
• existing key: keys like [root[key], ..., parent[key], self[key]]
• not existing key: indices like [root.index, ..., parent.index, self.index]

tree.parent(id)

Get parent node of the target node.

Parameters:

• id {String|Number} - Target node id

Returns: {Object|null} - Parent node or null

tree.filter(condition)

Filter tree nodes by condition.

Parameters:

• condition {Function} - Filter function (receives node, returns boolean)

Returns: {Array} - Filtered tree array

tree.sub(id)

Get subtree rooted at target node.

Parameters:

• id {String|Number} - Target node id

Returns: {Array} - Subtree array

tree.getDepth()

Get the maximum depth of the tree.

Returns: {Number} - Tree depth