Swift从JSON请求生成泛型函数

import Foundation

struct Response<T: Codable>: Codable {
    let data: T
}

func fetchData<T: Codable>(from url: URL, completion: @escaping (Result<T, Error>) -> Void) {
    URLSession.shared.dataTask(with: url) { data, response, error in
        if let error = error {
            completion(.failure(error))
            return
        }
        
        guard let data = data else {
            completion(.failure(NSError(domain: "com.example", code: 0, userInfo: nil)))
            return
        }
        
        do {
            let decoder = JSONDecoder()
            let response = try decoder.decode(Response<T>.self, from: data)
            completion(.success(response.data))
        } catch {
            completion(.failure(error))
        }
    }.resume()
}

struct User: Codable {
    let name: String
    let age: Int
}

let url = URL(string: "https://example.com/api/users")!
fetchData(from: url) { (result: Result<[User], Error>) in
    switch result {
    case .success(let users):
        print(users)
    case .failure(let error):
        print(error)
    }
}