tree-node-data

tree-node-data assigns a set of structure meta data for each node in your tree data structure.

Meta data includes parent, prev, prevSibling, next, nextSibling, siblingIndex, ancestors, numDescendants, numChildren.

It is useful for building tree structure UI for data display and data traversal.

Install

npm install tree-node-data

Features

1. Fast. We use it to handle 4000+ nodes tree in production with no obvious delay.
2. Clean. All added data are contained in the nodeData field; Original tree node data is intact.

Example

In short, it provides a function that assigns an extra field named nodeData to each node of your tree.

See it live here.

Origin

Result

[{ name: 'Software', key: 1, children: [ { name: 'Graphic software', key: 2, children: [ { name: 'Photoshop', key: 4, }, { name: 'Adobe CS3', key: 5, } ] } ] }]

[{ name: 'Software', key: 1, children: [{ name: 'Graphic software', key: 2, children: [{ name: 'Photoshop', key: 4, nodeData: { parent: 2, prev: 2, prevSibling: null, next: 5, nextSibling: 5, siblingIndex: 0, ancestors: [1, 2], numDescendants: 0, numChildren: 0 } }, { name: 'Adobe CS3', key: 5, nodeData: { parent: 2, prev: 4, prevSibling: 4, next: null, nextSibling: null, siblingIndex: 1, ancestors: [1, 2], numDescendants: 0, numChildren: 0 } }], nodeData: { parent: 1, prev: 1, prevSibling: null, next: 4, nextSibling: null, siblingIndex: 0, ancestors: [1], numDescendants: 2, numChildren: 2 } }], nodeData: { parent: null, prev: null, prevSibling: null, next: 2, nextSibling: null, siblingIndex: null, ancestors: [], numDescendants: 2, numChildren: 1 } }];

Node Data

Field	Description
parent	key value of parent node
prevSibling	key value of previous sibling node. null if the current node has no previous sibling node. i.e. it is the first/only child of its parent.
nextSibling	key value of next sibling node. null if the current node has no next sibling node. i.e. it is the last/only child of its parent.
prev	key value of previous node. Previous node is defined as previous sibling if found or parent node.
next	key value of next node. Next node is defined as next sibling node if found. Otherwise, it will be the 'nextSibling' of the closest ancestor that has a 'nextSibling';
siblingIndex	The integer index of the current node amongst its siblings. Index starts from 0.
ancestors	Array of key values of all ancestor nodes. This is useful for working out branch collapsed/expanded status.
numDescendants	This is the number of leaf nodes. This is useful for showing all items under a branch node.
numChildren	number of direct child nodes.

API

import assignNodeData from 'tree-node-data';

const config = {
  childrenField: 'children', // e.g. customise the field for children nodes. e.g. 'subItems', default 'children'
  keyField: 'key', // e.g. customise the field for node key. e.g. 'id', default 'key'
};

const nodesWithData = assignNodeData(
  nodes, // array of tree nodes. 
  config,
)

Tips

1. All nodes should have a distinct 'key' value.
2. If you want to process a tree instead of an array of nodes, wrap the root node in an array as the parameter to assignNodeData;
3. You may also want to use tree-node-util for looking up nodes from a tree using key values made available in 'nodeData'.
4. tree-node-util and tree-node-data together provides the powerful tools for building complex tree data structure UIs;