toJson method
Implementation
Map<String, dynamic> toJson() {
final json = <String, dynamic>{};
json['\$type'] = this.runtimeType.toString().let((type) {
final regExp = new RegExp(r'([A-Za-z0-9]*)(<.>)?');
return regExp.firstMatch(type)!.group(1);
});
json[r'predicate'] = predicate;
return json;
}