toJson method
Implementation
Map<String, dynamic> toJson() {
return <String, dynamic>{
if (id != null) r'id': id,
if (type != null) r'type': type,
if (name != null) r'name': name,
if (description != null) r'description': description,
if (color != null) r'color': color,
if (progression != null) r'progression': progression,
};
}