Decode an array inside JSON data only using Swift 4 Codable - swift

Question

I'm using Swift 4 Codable and I'm receiving this JSON from my web service:
{
"status": "success",
"data": {
"time": "00:02:00",
"employees": [
{
"id": 001,
"name": "foo"
},
{
"id": 002,
"name": "bar"
}
]
}
}
I want to decode only employees array into employee objects (the time property will only be saved once), but nothing works.
I read a lot of materials about Swift 4 Codable but don't get how can I decode this array.
EDIT: My employee class:
import Foundation
struct Employee: Codable {
var id: Int
var time: Date
enum CodingKeys: String, CodingKey {
case id = "id"
case time = "time"
}
}
The request:
Alamofire.SessionManager.default.request(Router.syncUsers)
.validate(contentType: ["application/json"])
.responseJSON { response in
if response.response?.statusCode == 200 {
guard let jsonDict = response as? Dictionary<String, Any>,
let feedPage = Employee(from: jsonDict as! Decoder) else {
return
}
guard let response = response.result.value as? [String: Any] else {
return
}
guard let data = response["data"] as? [String: Any] else {
return
}
guard let users = data["employees"] else {
return
}
guard let usersData = try? JSONSerialization.data(withJSONObject: users, options: .prettyPrinted) else {
return
}
guard let decoded = try? JSONSerialization.jsonObject(with: usersData, options: []) else {
return
}
let decoder = JSONDecoder()
guard let employee = try? decoder.decode(Employee.self, from: usersData) else {
print("errorMessage")
return
}
} else {
print("errorMessage")
}
}

Answer 1

When using Codable you cannot decode inner data without decoding the outer.
But it's pretty simple, for example you can omit all CodingKeys.
struct Root : Decodable {
let status : String
let data : EmployeeData
}
struct EmployeeData : Decodable {
let time : String
let employees : [Employee]
}
struct Employee: Decodable {
let id: Int
let name: String
}
let jsonString = """
{
"status": "success",
"data": {
"time": "00:02:00",
"employees": [
{"id": 1, "name": "foo"},
{"id": 2, "name": "bar"}
]
}
}
"""
do {
let data = Data(jsonString.utf8)
let result = try JSONDecoder().decode(Root.self, from: data)
for employee in result.data.employees {
print(employee.name, employee.id)
}
} catch { print(error) }

Answer 2

You can solve this kind of JSON parsing problem very easily with quicktype. Just paste in your JSON on the left and you'll get types and serialization/deserialization code on the right, for a variety of languages. Here are the types it produces for your JSON:
struct Employees: Codable {
let status: String
let data: EmployeesData
}
struct EmployeesData: Codable {
let time: String
let employees: [Employee]
}
struct Employee: Codable {
let id: Int
let name: String
}