Hello,
there is error in your library at source code:
...
if (this.isConnected) {
let connector = args.source.connectors[0];
let nodeEndId = this.endPoint === 'ConnectorSourceEnd' ? 'sourceID' : 'targetID';
let portEndId = this.endPoint === 'ConnectorSourceEnd' ? 'sourcePortID' : 'targetPortID';
...
It is even visible in your documentation.
It happens if you draw connector, but you do not connect it.
ERROR Error: Uncaught (in promise): TypeError: Cannot read property '0' of undefined
TypeError: Cannot read property '0' of undefined
at ConnectorDrawingTool.<anonymous> (ej2-diagrams.es2015.js:21617)
at Generator.next (<anonymous>)
at ej2-diagrams.es2015.js:21242
at new ZoneAwarePromise (:4200/polyfills.js:4111)
at push../node_modules/@syncfusion/ej2-diagrams/dist/es6/ej2-diagrams.es2015.js.__awaiter$1 (ej2-diagrams.es2015.js:21238)
at ConnectorDrawingTool.mouseUp (ej2-diagrams.es2015.js:21607)
at ConnectorDrawingTool.<anonymous> (ej2-diagrams.es2015.js:22645)
at Generator.next (<anonymous>)
at ej2-diagrams.es2015.js:21242
at new ZoneAwarePromise (:4200/polyfills.js:4111)
at resolvePromise (:4200/polyfills.js:4032)
at new ZoneAwarePromise (:4200/polyfills.js:4114)
at push../node_modules/@syncfusion/ej2-diagrams/dist/es6/ej2-diagrams.es2015.js.__awaiter$1 (ej2-diagrams.es2015.js:21238)
at ConnectorDrawingTool.mouseUp (ej2-diagrams.es2015.js:21607)
at ConnectorDrawingTool.<anonymous> (ej2-diagrams.es2015.js:22645)
at Generator.next (<anonymous>)
at ej2-diagrams.es2015.js:21242
at new ZoneAwarePromise (:4200/polyfills.js:4111)
at push../node_modules/@syncfusion/ej2-diagrams/dist/es6/ej2-diagrams.es2015.js.__awaiter$1 (ej2-diagrams.es2015.js:21238)
at ConnectorDrawingTool.mouseUp (ej2-diagrams.es2015.js:22637)