Swift使用API请求重构嵌套函数

import Foundation

func fetchData(completion: @escaping (Result<Data, Error>) -> Void) {
    guard let url = URL(string: "https://api.example.com/data") else {
        completion(.failure(NSError(domain: "Invalid URL", code: 0, userInfo: nil)))
        return
    }
    
    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: "No data", code: 0, userInfo: nil)))
            return
        }
        
        completion(.success(data))
    }.resume()
}

fetchData { result in
    switch result {
    case .success(let data):
        // 处理获取到的数据
        print(data)
    case .failure(let error):
        // 处理错误
        print(error)
    }
}