toJson method
Implementation
Map<String, Object?> toJson() => {
'id': id,
'label': label,
if (description != null) 'description': description,
if (fields.isNotEmpty) 'fields': [for (var f in fields) f.toJson()],
if (durationKey != null) 'durationKey': durationKey,
if (itemActions.isNotEmpty)
'itemActions': [for (var a in itemActions) a.toJson()],
};