RadarDataPoint constructor
Creates a radar data point.
label must not be empty. value must be a non-negative finite number or numeric string.
showValue defaults to true to display the value on the chart.
Throws an AssertionError if value is negative or not finite,
or if label is empty.
Implementation
RadarDataPoint({
required this.label,
required dynamic value,
this.showValue = true,
}) : value = _parseValue(value);