Using array of mixed Encodable types (in Swift)

AnyEncodable.swift

import UIKit

/// A type eraser to erase the concrete types of your encodable objects
struct AnyEncodable: Encodable {
    private let encodeClosure: (Encoder) throws -> Void

    init<T: Encodable>(_ value: T) {
        encodeClosure = { encoder in
            try value.encode(to: encoder)
        }
    }

    func encode(to encoder: Encoder) throws {
        try encodeClosure(encoder)
    }
}

// Define a common protocol for all encodable objects
protocol Vehicle: Encodable {}

// Conform all your encodable objects to this protocol
struct PetrolCar: Vehicle {
    let name: String = "Petrol Car"
    let manufacturer: String = "Ford"
    let petrolTankCapacity: Int = 50
}

struct ElectricCar: Vehicle {
    let name: String = "Electric Car"
    let manufacturer: String = "Tesla"
    let batteryCapacity: Int = 75
}

struct GasCar: Vehicle {
    let name: String = "Gas Car"
    let manufacturer: String = "Renault"
    let gasTankCapacity: Int = 55
}

struct F1Car: Vehicle {
    let name: String = "SF-24"
    let manufacturer: String = "Ferrari"
    let petrolTankCapacity: Int = 50
    let batteryCapacity: Int = 10
    let frontWing: Bool = true
    let rearWing: Bool = true
}

// APPROACH TO AVOID
struct MixedVehicles: Vehicle {
    let name: String
    let manufacturer: String
    let petrolTankCapacity: Int?
    let gasTankCapacity: Int?
    let batteryCapacity: Int?
}

// Create an array of type-erased encodable objects
let vehicles: [AnyEncodable] = [
    AnyEncodable(PetrolCar()),
    AnyEncodable(ElectricCar()),
    AnyEncodable(GasCar()),
    AnyEncodable(F1Car())
]

do {
    let jsonData = try JSONEncoder().encode(vehicles)
    print(String(decoding: jsonData, as: UTF8.self))
} catch {
    print("Error encoding JSON: \(error)")
}

// OUTPUT:
// [{"petrolTankCapacity":50,"manufacturer":"Ford","name":"Petrol Car"},{"name":"Electric Car","manufacturer":"Tesla","batteryCapacity":75},{"name":"Gas Car","manufacturer":"Renault","gasTankCapacity":55},{"name":"SF-24","manufacturer":"Ferrari","batteryCapacity":10,"petrolTankCapacity":50,"frontWing":true,"rearWing":true}]

OUTPUT:

[
    {
        "petrolTankCapacity": 50,
        "manufacturer": "Ford",
        "name": "Petrol Car"
    },
    {
        "name": "Electric Car",
        "manufacturer": "Tesla",
        "batteryCapacity": 75
    },
    {
        "name": "Gas Car",
        "manufacturer": "Renault",
        "gasTankCapacity": 55
    },
    {
        "name": "SF-24",
        "manufacturer": "Ferrari",
        "batteryCapacity": 10,
        "petrolTankCapacity": 50,
        "frontWing": true,
        "rearWing": true
    }
]