Flutter Model design pattern - flutter

Question

i have a Product Model
class Product {
int id;
String title;
double mrp;
Product(this.id, this.title, this.mrp);
factory Product.fromJson(int id, String title, double mrp) {
return Product(id, title, mrp);
}
}
I have different json structure for API calls when i get json data as response from server -
1st Example
{
"id": 523,
"title": "test",
"mrp": 23.25
}
2nd Example :
{
"id" : 523,
"title" : "test",
"mrp" : 23.25
"discountedPrice" : 23.00
}
3rd Example :
{
"id" : 523,
"title" : "test",
"mrp" : 23.25
"availableForSale" : true
}
4th Example :
{
"id" : 523,
"title" : "test",
"mrp" : 23.25
"firstCharacterTitle" : "T"
}
As you can see i have different new field like discountedPrice firstCharacterTitle availableForSale API structure in different fetching call of API. and it can be many others in other scenario.
What should i do with Product Model in different cases as i have only 3 permanent fields id title mrp but all others are dependent on scenario ? Should i keep increasing field in my model or anything else? What is the best Practise?

Answer 1

Sorry for longer answer.
You have 2 options
adding those extra parameters and make them nullable.
class Product {
int id;
String title;
double mrp;
String? firstCharacterTitle;
Product(this.id, this.title, this.mrp, {this.firstCharacterTitle});
factory Product.fromJson(
int id,
String title,
double mrp, {
String? firstCharacterTitle,
}) {
return Product(id, title, mrp, firstCharacterTitle: firstCharacterTitle);
}
}
Or work with something dynamic
class Product {
int id;
String title;
double mrp;
Map<String, dynamic> extraParams;
Product(this.id, this.title, this.mrp, this.prms);
factory Product.fromJson(int id, String title, double mrp, Map<String, dynamic> prms) {
return Product(id, title, mrp, prms);
}
}
I also recommend using json_serializable. Cause your fromJson method is not truly fromJson, but it's taking already converted Json parameters.