netClustering allows you to detect clusters in networks using the Clauset, Newman and Moore community detection algorithm directly from the browser, as simple as:
netClustering.cluster(nodes, edges);
and the clusters will be stored in the .cluster attribute of the nodes.
The code is based on an implementation created by Robin W. Spencer for his site scaledinnovation.com, I wrapped it up on a container so it could be reused as a library