Javascript tree traversal and manipulation library

Usage no npm install needed!

<script type="module">
  import arboreal from '';



A micro-library for traversing and manipulating tree-like data structures in JavaScript; works with both node.js and the browser.


In node.js:

git clone git://
npm install

To use it in the browser, just load lib/arboreal.js in a script tag.


Arboreal provides a set of methods for parsing, manipulating, and traversing tree like data structures. A tree can be created from scratch and then extended with child elements.

var tree = new Arboreal()


For each child node, Arboreal will automatically assign an id string representing the depth and the index the position of the node within the tree structure.


// => 0/0/1

Alternatively, Arboreal can also parse an existing object into a tree (though it will need to know the name of the 'children' attribute).

var wikipediaJsCategory = {
  category: 'JavaScript',
  subcategories: [
    {category: 'Ajax (programming)'},
    {category: 'JavaScript engines'},
    {category: 'JavaScript programming languages family',
     subcategories: [{
       category: 'JavaScript dialect engines'
    {category: 'JavaScript based calendar components'},
    {category: 'JavaScript based HTML editors'}

var tree = Arborel.parse(wikipediaJsCategory, 'subcategories');

Also several children (or even the whole tree) can be added at the same time (syntax is similar as parse)

var tree = new Arboreal();
tree.children[1].appendChildren({category:'C#', subitems:[{category:'WPF'}]}, "subitems" );


An Arboreal object can be traversed either upwards or downwards.

function iterator (node) {
  var depth = "", i;
  for (i = 1; i <= node.depth; i++) depth += ">>";[depth,].join(" "));


// =>   JavaScript
//      >> Ajax (programming)
//      >> JavaScript engines
//      >> JavaScript produgramming languages family
//      >>>> JavaScript dialect engines
//      >> JavaScript based calendar components
//      >> JavaScript based HTML editors


//  => >> JavaScript produgramming languages family
//     >>>> JavaScript dialect engines
//      JavaScript
//     >> Ajax (programming)
//     >> JavaScript engines
//     >> JavaScript based calendar components
//     >> JavaScript based HTML editors

Note that in both the traverseDown and the traverseUp methods, the value of this in the iterator is bound to the value of the currently traversed node. Our iterator function can in fact be rewritten as:

function iterator () {
  var depth = "", i;
  for (i = 1; i <= this.depth; i++) depth += ">>";[depth,].join(" "));

Arboreal object can be iterated up to the root using method 'bubbleUp':


//  => >>>> JavaScript dialect engines
//     >> JavaScript programming languages family
//     JavaScript


In order to search for a single node into an arboreal object, one can use the find method.

tree.find(function (node) {
  return (/calendar/).test(

// =>  JavaScript based calendar components

The find method will also accept a string as an argument. In that case, it will try to find a node by id.


// => JavaScript dialect engines


While traversing a tree, nodes can be deleted by calling the remove method on the node object bound to the iterator function.


// => 7

tree.traverseDown(function (item) {
  var toDelete = 'JavaScript programming languages family';
  if ( === toDelete) {


// 5


Arboreal test suite uses Jasmine. To run it in node.js..

cd /home/me/code/arboreal && npm test

To run it in the browser, just open the test/index.html


A minified version of Arboreal can be generated by running

node make.js