TypeError: Cannot read property 'nodeName' of null
at create (svg.js:3806)
at SVG.SVG (svg.js:26)
at ConceptMapController.setupSVG (conceptMapController.es6:2595)
at ConceptMapController.eval (conceptMapController.es6:345)
at Scope.$digest (angular.js:17527)
at Scope.$apply (angular.js:17793)
at done (angular.js:11834)
at completeRequest (angular.js:12036)
at XMLHttpRequest.requestLoaded (angular.js:11969)