Network Clustering fixes on usage joinCondition for clusterOutliers() (…

…#3388)

Fix for #3367

Changes:

- Clustered nodes with shared connections are added to the same cluster
- joinCondition value `null` handled as `undefined`
- Fixed bug on adding clusters if joinCondition present and returns true

Unit tests have been added to `Network.test.js` for these changes.

lib/network/modules/Clustering.js

@@ -195,17 +195,17 @@ class ClusterEngine {
     options = this._checkOptions(options);
     let clusters = [];
     let usedNodes = {};
-    let edge, edges, node, nodeId, relevantEdgeCount;
+    let edge, edges, relevantEdgeCount;
     // collect the nodes that will be in the cluster
     for (let i = 0; i < this.body.nodeIndices.length; i++) {
       let childNodesObj = {};
       let childEdgesObj = {};
-      nodeId = this.body.nodeIndices[i];
+      let nodeId = this.body.nodeIndices[i];
+      let node = this.body.nodes[nodeId];
 
       // if this node is already used in another cluster this session, we do not have to re-evaluate it.
       if (usedNodes[nodeId] === undefined) {
         relevantEdgeCount = 0;
-        node = this.body.nodes[nodeId];
         edges = [];
         for (let j = 0; j < node.edges.length; j++) {
           edge = node.edges[j];
@@ -219,35 +219,73 @@ class ClusterEngine {
 
         // this node qualifies, we collect its neighbours to start the clustering process.
         if (relevantEdgeCount === edgeCount) {
+          var checkJoinCondition = function(node) {
+            if (options.joinCondition === undefined || options.joinCondition === null) {
+              return true;
+            }
+
+            let clonedOptions = NetworkUtil.cloneOptions(node);
+            return options.joinCondition(clonedOptions);
+          }
+
           let gatheringSuccessful = true;
           for (let j = 0; j < edges.length; j++) {
             edge = edges[j];
             let childNodeId = this._getConnectedId(edge, nodeId);
             // add the nodes to the list by the join condition.
-            if (options.joinCondition === undefined) {
+            if (checkJoinCondition(node)) {
               childEdgesObj[edge.id] = edge;
-              childNodesObj[nodeId] = this.body.nodes[nodeId];
+              childNodesObj[nodeId] = node;
               childNodesObj[childNodeId] = this.body.nodes[childNodeId];
               usedNodes[nodeId] = true;
-            }
-            else {
-              let clonedOptions = NetworkUtil.cloneOptions(this.body.nodes[nodeId]);
-              if (options.joinCondition(clonedOptions) === true) {
-                childEdgesObj[edge.id] = edge;
-                childNodesObj[nodeId] = this.body.nodes[nodeId];
-                usedNodes[nodeId] = true;
-              }
-              else {
-                // this node does not qualify after all.
-                gatheringSuccessful = false;
-                break;
-              }
+            } else {
+              // this node does not qualify after all.
+              gatheringSuccessful = false;
+              break;
             }
           }
 
           // add to the cluster queue
           if (Object.keys(childNodesObj).length > 0 && Object.keys(childEdgesObj).length > 0 && gatheringSuccessful === true) {
-            clusters.push({nodes: childNodesObj, edges: childEdgesObj})
+            /**
+             * Search for cluster data that contains any of the node id's
+             * @returns {Boolean} true if no joinCondition, otherwise return value of joinCondition
+             */
+            var findClusterData = function() {
+              for (var n in clusters) {
+                // Search for a cluster containing any of the node id's
+                for (var m in childNodesObj) {
+                  if (clusters[n].nodes[m] !== undefined) {
+                    return clusters[n];
+                  }
+                }
+              }
+
+              return undefined;
+            };
+
+
+            // If any of the found nodes is part of a cluster found in this method,
+            // add the current values to that cluster
+            var foundCluster = findClusterData();
+            if (foundCluster !== undefined) {
+              // Add nodes to found cluster if not present
+              for (let m in childNodesObj) {
+                if (foundCluster.nodes[m] === undefined) {
+                  foundCluster.nodes[m] = childNodesObj[m];
+                }
+              }
+
+              // Add edges to found cluster, if not present
+              for (let m in childEdgesObj) {
+                if (foundCluster.edges[m] === undefined) {
+                  foundCluster.edges[m] = childEdgesObj[m];
+                }
+              }
+            } else {
+              // Create a new cluster group
+              clusters.push({nodes: childNodesObj, edges: childEdgesObj})
+            }
           }
         }
       }