Swift 5 Parsing strange json format - json

Question

I'm trying to parse JSON but keep getting incorrect format error. The JSON I get back from FoodData Central (the USDA's Nutrition API) is as follows:
{
dataType = "Survey (FNDDS)";
description = "Chicken thigh, NS as to cooking method, skin not eaten";
fdcId = 782172;
foodNutrients = (
{
amount = "24.09";
id = 9141826;
nutrient = {
id = 1003;
name = Protein;
number = 203;
rank = 600;
unitName = g;
};
type = FoodNutrient;
},
{
amount = "10.74";
id = "9141827";
nutrient = {
id = 1004;
name = "Total lipid (fat)";
number = 204;
rank = 800;
unitName = g;
};
type = FoodNutrient;
}
);
}
My Structs:
struct Root: Decodable {
let description: String
let foodNutrients: FoodNutrients
}
struct FoodNutrients: Decodable {
// What should go here???
}
From the JSON, it looks like foodNutrients is an array of unnamed objects, each of which has the values amount: String, id: String, and nutrient: Nutrient (which has id, name etc...) However, forgetting the Nutrient object, I can't even parse the amounts.
struct FoodNutrients: Decodable {
let amounts: [String]
}
I don't think its an array of string, but I have no idea what the () in foodNutrients would indicate.
How would I go about parsing this JSON. I'm using Swift 5 and JSONDecoder. To get the JSON I use JSONSerializer, then print out the JSON above.

Answer 1

This is not a JSON. This is a property list in the openStep format.
This is how it can be modelled (use String instead of Int):
struct Root: Decodable {
let description: String
let foodNutrients: [FoodNutrient]
}
struct FoodNutrient: Decodable {
let id: String
let amount: String
let nutrient: Nutrient
}
struct Nutrient: Decodable {
let name: String
let number: String
let rank: String
let unitName: String
}
And then decode it like this:
try PropertyListDecoder().decode(Root.self, from: yourStr)

Answer 2

The () in foodNutrients indicates that it holds an array of objects - in that case FoodNutrient objects. Therefore your root object should look like this:
struct Root: Decodable {
let description: String
let foodNutrients: [FoodNutrient]
}
Now the foodNutrient is except for the nutrient object straightforward:
struct FoodNutrient: Decodable {
let id: Int // <-- in your example it is an integer and in the second object a string, choose the fitting one from the API
let amount: String
let nutrient: Nutrient
}
And the nutrient object should look like this:
struct Nutrient: Decodable {
let name: String
let number: Int
let rank: Int
let unitName: String
}
Using Decodable is a good and easy way to serialize JSON. Hope that helps. Happy coding :)