Making your first call with URLSession

Let's take a look at the anatomy of a simple URL task:

let url = URL(string: "https://api.website.com/")!
let task  = URLSession.shared.dataTask(url: url) { data, response, error in 
    if let error = error { return } // handle the error somehow
    guard let response = response as HTTPURLResponse,
        let data = data else { return }
    // data: Data is set, and all good
}
task.resume()

If the call has succeeded, the data variable will be set and will contain the data downloaded from the remote server.