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 instance
// tree.tree is tree structure data
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 by id
const parent = tree.parent(4) // { id: 2, ... }

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

// Get subtree by id
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 instance.

Parameters:

• array {Array} - Flattened tree data array
• config {Object} - Optional configuration

Returns: {Tree} - Tree instance

new Tree(tree, config = {})

Create a new Tree instance.

Parameters:

• tree {Array} - Tree structure data array
• config {Object} - Optional configuration

Returns: {Tree} - Tree instance

tree.toArray()

Convert tree back to flattened array.

Returns: {Array} - Flattened tree array

tree.path(id, key = undefined)

Get the path from root to target node.

Parameters:

• id {String|Number} - Target node ID
• key {String|null|undefined} - Property key to return

Returns: {Array} - Path array containing nodes, specified keys, or indices

• key exists: Returns keys like [root[key], ..., parent[key], self[key]]
• key is null: Returns indices like [root.index, ..., parent.index, self.index]
• key is undefined: Returns nodes like [root, ..., parent, self]

tree.parent(id)

Get the 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 the subtree rooted at target node.

Parameters:

• id {String|Number} - Target node ID

Returns: {Tree|null} - Subtree instance or null

tree.getDepth()

Get the maximum depth of the tree.

Returns: {Number} - Tree depth