swift4创建用户信息名称、年龄并从fire base获取数据

import Firebase

struct UserInfo {
    var name: String
    var age: Int
}

func getUserInfo(completion: @escaping (UserInfo?) -> Void) {
    let ref = Database.database().reference().child("users")
    
    ref.observeSingleEvent(of: .value) { (snapshot) in
        guard let userInfoDict = snapshot.value as? [String: Any] else {
            completion(nil)
            return
        }
        
        let name = userInfoDict["name"] as? String ?? ""
        let age = userInfoDict["age"] as? Int ?? 0
        
        let userInfo = UserInfo(name: name, age: age)
        completion(userInfo)
    }
}