template/html/d3-graph.js
function isConnected(targetNode, otherNode)
   {
      return targetNode.index === otherNode.index || linkedByIndex[targetNode.index + ',' + otherNode.index];
   }
function isConnected(targetNode, otherNode)
   {
      return targetNode.index === otherNode.index || linkedByIndex[targetNode.index + ',' + otherNode.index];
   }
Checks if a target node is connected to another given node by checking `index` or the `linkedByIndex` map.

@param {object}   targetNode
@param {object}   otherNode

@returns {boolean}