Combine Many Merge Pokemon API

main.swift

//
//  ViewController.swift
//  Pokemon
//
//  Created by Ihwan ID on 04/02/21.
//

import UIKit
import Combine

struct PokemonResponse: Codable{

    let results: [Pokemon]
}

struct Pokemon: Codable{
    let name: String
    let url: String
}

struct PokemonDetailResponse: Codable{
    let id: Int
    let name: String
    let height: Int
    let weight: Int
    let types: [Types]
}

struct Types: Codable{
    let slot: Int
    let type: Type
}


struct Type: Codable{
    let name: String
}


class ViewController: UIViewController {

    private let urlString = "https://pokeapi.co/api/v2/pokemon/"
    private var pokemonSubscriber: AnyCancellable?



    override func viewDidLoad() {
        super.viewDidLoad()

        self.pokemonSubscriber = URLSession.shared.dataTaskPublisher(for: URL(string: urlString)!)
            .map{$0.data}
            .decode(type: PokemonResponse.self, decoder: JSONDecoder())
            .tryMap { pokemons -> [String] in
                return pokemons.results.map{$0.url}
            }
            .flatMap { urls in
                return self.getFullData(input: urls)
            }
            .sink(receiveCompletion: { (completion) in
                print(completion)
            }, receiveValue: { (pokemons) in
                for pokemon in pokemons{
                    print("\(pokemon.name): \(pokemon.types.map{$0.type.name})")
                }
            })
    }


    func createRequest(from id: String) -> AnyPublisher<PokemonDetailResponse, Error>{

        let url = URL(string: id)!

        return URLSession.shared.dataTaskPublisher(for: url)
            .map { $0.data }
            .decode(type: PokemonDetailResponse.self, decoder: JSONDecoder())
            .receive(on: RunLoop.main)
            .eraseToAnyPublisher()
    }

    func getFullData(input: [String]) -> AnyPublisher<[PokemonDetailResponse], Error>{
        let requests = input.compactMap { res in
            return self.createRequest(from: res)
        }
        return Publishers.MergeMany(requests)
            .compactMap { $0}
            .collect()
            .eraseToAnyPublisher()

    }

}