Dart Convert List as Map Entry for JSON Encoding - dart

Question

I asked a question before about Dart encoding/decoding to JSON, however, the libraries that were suggested were not complete and I decided to manually handle that.
The objective is to convert these objects to a map.
class Parent extends Object {
int id;
String name;
List<Child> listChild = new List<Child>();
Map toMap() => {"id":id, "name":name, "listChild":listChild};
}
class Child extends Object {
int id;
String childName;
Map toMap() => {"id":id, "childName":childName};
}
When doing
print(JSON.encode(parent.toMap()));
I am seeing it go here, any suggestion how to make this work?
if (!stringifyJsonValue(object)) {
checkCycle(object);
try {
var customJson = _toEncodable(object);
if (!stringifyJsonValue(customJson)) {
throw new JsonUnsupportedObjectError(object);
}
_removeSeen(object);
} catch (e) {
throw new JsonUnsupportedObjectError(object, cause : e);
}
}
}

Answer 1

Map toMap() => {"id":id, "name":name: "listChild": listChild.map((c) => c.toJson().toList())};
is valid for JSON.
import 'dart:convert' show JSON;
...
String json = JSON.encode(toMap());
You can also use the toEncodeable callback - see How to convert DateTime object to json

Answer 2

If your class structure does not contain's any inner class then follow
class Data{
String name;
String type;
Map<String, dynamic> toJson() => {
'name': name,
'type': type
};
}
If your class uses inner class structure
class QuestionTag {
String name;
List<SubTags> listSubTags;
Map<String, dynamic> toJson() => {
'name': name,
'listSubTags': listSubTags.map((tag) => tag.toJson()).toList()
};
}
class SubTags {
String tagName;
String tagDesc;
SubTags(this.tagName, this.tagDesc);
Map<String, dynamic> toJson() => {
'tagName': tagName,
'tagDesc': tagDesc,
};
}

Answer 3

Just rename Map toMap() into Map toJson() and it will work fine. =)
void encode() {
Parent p = new Parent();
Child c1 = new Child();
c1 ..id = 1 ..childName = "Alex";
Child c2 = new Child();
c2 ..id = 2 ..childName = "John";
Child c3 = new Child();
c3 ..id = 3 ..childName = "Jane";
p ..id = 1 ..name = "Lisa" ..listChild = [c1,c2,c3];
String json = JSON.encode(p);
print(json);
}
class Parent extends Object {
int id;
String name;
List<Child> listChild = new List<Child>();
Map toJson() => {"id":id, "name":name, "listChild":listChild};
}
class Child extends Object {
int id;
String childName;
Map toJson() => {"id":id, "childName":childName};
}