This document discusses encoding and decoding data from different file formats like JSON and plist into Swift structs and classes. It shows examples of using the Codable protocol to decode and encode structs from files into objects, retrieving properties values from the decoded objects. It also defines a Friend struct that conforms to Codable and contains nested types to be encoded and decoded from files.

2. typealias Codable = Decodable & Encodable

3. protocol Decodable
protocol Encodable

10. let fileURL: URL = URL(fileURLWithPath: "file.plist")
guard let plistDic: [String:Any] =
NSDictionary(contentsOf: fileURL) as? [String:Any]
else { return }
if let age: Int = plistDic["age"] as? Int {
print(age)
}
if let name: String = plistDic["name"] as? String {
print(name)
}

11. let fileURL: URL = URL(fileURLWithPath: "file.plist")
let data: Data = try! Data(contentsOf: fileURL)
let plistDecoder: PropertyListDecoder =
PropertyListDecoder()
let friend: Friend = try!
plistDecoder.decode(Friend.self, from: data)
print(friend.name)
print(friend.age)

13. let fileURL: URL = URL(fileURLWithPath: "file.json")
let data: Data = try! Data(contentsOf: fileURL)
guard let jsonObject: Any = try?
JSONSerialization.jsonObject(with: data,
options: .allowFragments) else { return }
guard let jsonDic: [String:Any] = jsonObject as?
[String:Any] else { return }
if let age: Int = jsonDic["age"] as? Int {
print(age)
}
if let name: String = jsonDic["name"] as? String {
print(name)
}

14. let fileURL: URL = URL(fileURLWithPath: "file.json")
let data: Data = try! Data(contentsOf: fileURL)
let jsonDecoder: JSONDecoder = JSONDecoder()
let friend: Friend = try!
jsonDecoder.decode(Friend.self, from: data)
print(friend.name)
print(friend.age)

15. public protocol Encodable {
public func encode(to encoder: Encoder) throws
}
public protocol Decodable {
public init(from decoder: Decoder) throws
}

16. struct Friend: Codable {
let name: String
let age: Int
let job: String
let isSexy: Bool?
struct Address: Codable {
let country: String
let city: String
}
let address: Address
}