borderColor property Null safety

Color? borderColor

Customizes the border color of the spark area chart. The border will be rendered on the top of the spark area chart. To render the border, both the borderWidth and borderColor property needs to be set.

Defaults to null.

Widget build(BuildContext context) {
 return Scaffold(
   body: Center(
       child: SfSparkAreaChart(
     borderWidth: 2,
     data: <double>[18, 24, 30, 14, 28],


final Color? borderColor;