getNumByValueDouble static method
fractionDigits == 0-20
Implementation
static num? getNumByValueDouble(double? value, int fractionDigits) {
  if (value == null) return null;
  String valueStr = value.toStringAsFixed(fractionDigits);
  return fractionDigits == 0
      ? int.tryParse(valueStr)
      : double.tryParse(valueStr);
}