visjs-network/lib/network/modules/components/nodes/Cluster.js

A dynamic, browser-based network visualization library.

let util = require('../../../../util')
let Node = require('../Node').default

/**
 * A Cluster is a special Node that allows a group of Nodes positioned closely together
 * to be represented by a single Cluster Node.
 *
 * @extends Node
 */
class Cluster extends Node {
  /**
   * @param {Object} options
   * @param {Object} body
   * @param {Array.<HTMLImageElement>}imagelist
   * @param {Array} grouplist
   * @param {Object} globalOptions
   * @param {Object} defaultOptions     Global default options for nodes
   */
  constructor(
    options,
    body,
    imagelist,
    grouplist,
    globalOptions,
    defaultOptions
  ) {
    super(options, body, imagelist, grouplist, globalOptions, defaultOptions)

    this.isCluster = true
    this.containedNodes = {}
    this.containedEdges = {}
  }

  /**
   * Transfer child cluster data to current and disconnect the child cluster.
   *
   * Please consult the header comment in 'Clustering.js' for the fields set here.
   *
   * @param {string|number} childClusterId  id of child cluster to open
   */
  _openChildCluster(childClusterId) {
    let childCluster = this.body.nodes[childClusterId]
    if (this.containedNodes[childClusterId] === undefined) {
      throw new Error(
        'node with id: ' + childClusterId + ' not in current cluster'
      )
    }
    if (!childCluster.isCluster) {
      throw new Error('node with id: ' + childClusterId + ' is not a cluster')
    }

    // Disconnect child cluster from current cluster
    delete this.containedNodes[childClusterId]
    util.forEach(childCluster.edges, edge => {
      delete this.containedEdges[edge.id]
    })

    // Transfer nodes and edges
    util.forEach(childCluster.containedNodes, (node, nodeId) => {
      this.containedNodes[nodeId] = node
    })
    childCluster.containedNodes = {}

    util.forEach(childCluster.containedEdges, (edge, edgeId) => {
      this.containedEdges[edgeId] = edge
    })
    childCluster.containedEdges = {}

    // Transfer edges within cluster edges which are clustered
    util.forEach(childCluster.edges, clusterEdge => {
      util.forEach(this.edges, parentClusterEdge => {
        // Assumption: a clustered edge can only be present in a single clustering edge
        // Not tested here
        let index = parentClusterEdge.clusteringEdgeReplacingIds.indexOf(
          clusterEdge.id
        )
        if (index === -1) return

        util.forEach(clusterEdge.clusteringEdgeReplacingIds, srcId => {
          parentClusterEdge.clusteringEdgeReplacingIds.push(srcId)

          // Maintain correct bookkeeping for transferred edge
          this.body.edges[srcId].edgeReplacedById = parentClusterEdge.id
        })

        // Remove cluster edge from parent cluster edge
        parentClusterEdge.clusteringEdgeReplacingIds.splice(index, 1)
      })
    })
    childCluster.edges = []
  }
}

export default Cluster