How can i parse data from json file to fl_chart in flutter?

I am new to flutter and i am trying to use fl_chart as a chart to my application. I am using the following Dummy code snippet which is running successfully but i want to parse data from local json from asset folder and use xvalue & yvalue from json to FlSpot.

LineChartBarData(
              spots: [
                FlSpot(0,0),
                FlSpot(1, 1),
                FlSpot(2, 3),
                FlSpot(3, 3),
                FlSpot(4, 5),
                FlSpot(4, 4)
              ],