Formally, a community detection aims to partition a graph’s vertices in subsets, such that there are many edges connecting between vertices of the same sub-set compared to vertices of different sub-sets; in essence, a community has many more ties between each constituent part than with outsiders. There are numerous algorithms present in the literature for solving this problem, a complete survey can be found in [1].

One of the popular community detection algorithms is presented in [2]. This algorithm separates the network in communities by optimizing greedily a modularity score after trying various grouping operations on the network. By using this simple greedy approach the algorithm is computationally very efficient.

[1] Fortunato, Santo. "Community detection in graphs." Physics Reports 486, no. 3-5 (2010).

[2] V.D. Blondel, J.-L. Guillaume, R. Lambiotte, E. Lefebvre. "Fast unfolding of communities in large networks." J. Stat. Mech., 2008: 1008.

(http://arxiv.org/abs/0803.0476) (http://en.wikipedia.org/wiki/Community_structure#The_Louvain_method).

0. Install the package from NPM

npm i --save louvain

1. Import the package.

let louvain = require('louvain');

2. Sample Data Format

let node_data = ['id1', 'id2', 'id3']; // any type of string can be used as id

let edge_data = [
	{source: 'id1', target:'id2', weight: 10.0},
	{source: 'id2', target:'id3', weight: 20.0}, 
	{source: 'id3', target:'id1', weight: 30.0}
];

let init_part = {'id1':0, 'id2':0, 'id3': 1}; 
// Object with ids of nodes as properties and community number assigned as value.

3. Run the Algorithm on your node and edge set by chaining the nodes and edges methods, optionally you can provide an intermediary community partition assignement with the partition_init method. [ Order of chaining is important ]

	
let community = louvain().nodes(node_data).edges(edge_data).partition_init(init_part);
let result  = community();

We can see the partitioned graph vertices with the help of color coding.

This has been tested with Node.js v6.11.5 / npm 5.5.1 - written in ES6

This, and all github.com/multivacplatform projects, are under the Multivac Platform Open Source Code of Conduct. Additionally, see the Typelevel Code of Conduct for specific examples of harassing behavior that are not tolerated.

Corneliu S. (jLouvain) [https://github.com/upphiminn/jLouvain]

The MIT License (MIT)