Additional changes for visjs#3500 (visjs#3525)

* Cleaned up some whitespace and added test for issue

* Checking for proper removal, better comments and whitespace cleanup

Author: justinharrell

lib/network/modules/EdgesHandler.js

@@ -426,11 +426,8 @@ class EdgesHandler {
    * so the right place to do call this is in the handler for event `_dataUpdated`.
    */
   _updateState() {
-
     this._addMissingEdges();
-
     this._removeInvalidEdges();
-    
   }
 
   /**
@@ -464,19 +461,17 @@ class EdgesHandler {
    * @private
    */ 
   _addMissingEdges() {
-    
      let edges = this.body.edges;
      let edgesData = this.body.data.edges;
      let addIds = [];
 
      edgesData.forEach((edgeData, edgeId) => {
          let edge = edges[edgeId];
-         if(edge===undefined)
-         {
+         if(edge===undefined) {
            addIds.push(edgeId);
          }
      });
- 
+     
      this.add(addIds,true);
    }  
 }

test/Network.test.js

@@ -610,6 +610,41 @@ describe('Edge', function () {
     assert.notEqual(edges[3].options.color.color, color); // Has own value
     assert.equal(edges[4].options.color.color, color);
   });
+
+  /**
+   * Unit test for fix of #3500
+   * Checking to make sure edges that become unconnected due to node removal get reconnected
+  */  
+  it('has reconnected edges', function () {
+    var node1 = {id:1, label:"test1"};
+    var node2 = {id:2, label:"test2"};
+    var nodes = new vis.DataSet([node1, node2]);
+  
+    var edge = {id:1, from: 1, to:2};
+    var edges = new vis.DataSet([edge]);
+
+    var data = {
+        nodes: nodes,
+        edges: edges
+    };    
+
+    var container = document.getElementById('mynetwork');
+    var network = new vis.Network(container, data);
+
+    //remove node causing edge to become disconnected
+    nodes.remove(node2.id);
+    
+    var foundEdge = network.body.edges[edge.id];
+
+    assert.ok(foundEdge===undefined, "edge is still in state cache");
+
+    //add node back reconnecting edge
+    nodes.add(node2);
+    
+    foundEdge = network.body.edges[edge.id];
+    
+    assert.ok(foundEdge!==undefined, "edge is missing from state cache");
+  });
 });  // Edge