类型'[Root]'的值没有成员'commit' . 我如何解码JSON根数组

我试图使用可编码解析JSON . 我能够解码它但它在根数组中，我无法通过它自己打印每个值 . 编译器抱怨说 Value of type '[Root]' has no member 'commit' . 如何更改此值以打印值 . 下面是JSON

[
    {
        "sha": "3f4227ec2894bb354b145deff9dbc1adc6b6d6f2",
        "node_id": "MDY6Q29tbWl0NDQ4Mzg5NDk6M2Y0MjI3ZWMyODk0YmIzNTRiMTQ1ZGVmZjlkYmMxYWRjNmI2ZDZmMg==",
        "commit": {
            "author": {
                "name": "Slava Pestov",
                "email": "sviatoslav.pestov@gmail.com",
                "date": "2018-08-12T08:09:22Z"
            }
        }
    },
    {
        "sha": "3f4227ec2894bb354b145deff9dbc1adc6b6d6f2",
        "node_id": "MDY6Q29tbWl0NDQ4Mzg5NDk6M2Y0MjI3ZWMyODk0YmIzNTRiMTQ1ZGVmZjlkYmMxYWRjNmI2ZDZmMg==",
        "commit": {
            "author": {
                "name": "Slava Pestov",
                "email": "sviatoslav.pestov@gmail.com",
                "date": "2018-08-12T08:09:22Z"
            }
        }
    }
]

我在这里解码它

struct Root: Decodable {
    let commit: Author
}

struct Author: Decodable {
    let author: People
}

struct People: Decodable {
    let name: String?
    let date: String?
    let email: String?
}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        getCommits()
    }


    func getCommits() {
        let urlString = "https://api.github.com/repos/apple/swift/commits"
        guard let url = URL(string: urlString) else {
            print("Couldn't fetch JSON")
            return
        }
        let session = URLSession.shared
        let dataTask = session.dataTask(with: url) { (data, response, error) in
            guard data != nil && error == nil else {
                print(data ?? "")
                return
            }
            do {
                let decoder = JSONDecoder()
                let result = try decoder.decode([Root].self, from: data!)
                print(result.commit)
                print(result.commit.author.name)
            } catch let decodeError {
                print("Failed to decode json:", decodeError)
            }
        }
        dataTask.resume()
    }
}

这是我在控制台中的输出 . 我希望能够只打印姓名，日期和电子邮件 .

[Gihhub.Commits（commit：Gihhub.Author）（作者：Gihhub.People（姓名：可选（“Slava Pestov”），日期：可选（“2018-08-12T08：09：22Z”），电子邮件：可选（“ sviatoslav.pestov@gmail.com“）））），Gihhub.Commits（commit：Gihhub.Author（作者：Gihhub.People（姓名：可选（”Slava Pestov“），日期：可选（”2018-08-12T03： 47：22Z“），电子邮件：可选（”spestov@apple.com“）））），Gihhub.Commits（提交：Gihhub.Author（作者：Gihhub.People（姓名：可选（”Slava Pestov“），日期：可选（“2018-08-12T03：47：08Z”），电子邮件：可选（“spestov@apple.com”））））]