How to convert object to json in flutter? - json

Question

I want to convert my object into JSON so I implemented following code
import "package:behoove/models/product.dart";
class Order {
Product _product;
int _quantity;
int _id;
Order(this._product, this._quantity, this._id);
int get id => _id;
int get quantity => _quantity;
Product get product => _product;
double get orderPrice => _quantity * double.parse(_product.discountedPrice ?? _product.price);
Map<String, dynamic> toJson() => {
"id": _product.id.toString(),
"name": _product.name,
"price": _product.price,
"quantity": _quantity.toString(),
"attributes": {},
"conditions": []
};
}
JSON from app is
{id: 9, name: GoldStar Classic 032, price: 1200, quantity: 1, attributes: {}, conditions: []}}
Screenshot JSON from app
But JSON from DartPad is
{"id":"1","name":"Sabin","price":200,"quantity":3,"attributes":{},"conditions":[]}
Screenshot JSON from DartPad console
How can I get same output on my app. please help. Also why is it not similar on both DartPad and app?

Answer 1

Instead of calling .toJson() directly use jsonEncode() as in the example (you can run it in DartPad to see difference). Calling jsonEncode(order) will give you a properly formatted json.
import 'dart:convert';
void main() {
final obj = Order();
print(obj.toJson());
print(jsonEncode(obj));
}
class Order {
int id = 0;
int price = 100;
String name = 'asdf';
int quantity = 10;
Map<String, dynamic> toJson() => {
"id": id.toString(),
"name": name,
"price": price,
"quantity": quantity.toString(),
"attributes": {},
"conditions": []
};
}
Output:
// simple toJson that ommits quotation marks
{id: 0, name: asdf, price: 100, quantity: 10, attributes: {}, conditions: []}
// properly encoded json
{"id":"0","name":"asdf","price":100,"quantity":"10","attributes":{},"conditions":[]}