Decode Data to Swift types using Combine framework

Let’s say we have a Decodable type User.

struct User: Decodable {
    let id: Int
    let name: String
}

We have a JSON data that represents the User type.

let jsonData = """
{
    "id": 1,
    "name": "John"
}
""".data(using: .utf8)!

We can decode the JSON data to User type in Combine using decode(type:decoder:) operator.

Just(jsonData)
    .decode(type: User.self, decoder: JSONDecoder())
    .sink { completion in
        print(completion)
    } receiveValue: { user in
        print(user)
    }

The complete code looks like this:

import Combine
import Foundation

struct User: Decodable {
    let id: Int
    let name: String
}

let jsonData = """
{
    "id": 1,
    "name": "John"
}
""".data(using: .utf8)!

Just(jsonData)
    .decode(type: User.self, decoder: JSONDecoder())
    .sink { completion in
        print(completion)
    } receiveValue: { user in
        print(user)
    }

When you run the above code, you will see the following output:

User(id: 1, name: "John")
finished