fromJson static method
Null when data is missing or not entirely numeric — a series the
client cannot plot is skipped, never plotted as zeros.
Implementation
static ChartDataset? fromJson(Map<String, dynamic> json) {
final data = _numbers(json['data']);
if (data == null) return null;
return ChartDataset(
label: json['label'] is String ? json['label'] as String : null,
data: data,
);
}