How to decode a nested JSON struct with Swift Decodable? - json

Question

Here is my JSON
{
"myItems": {
"item1name": [{
"url": "google.com",
"isMobile": true,
"webIdString": "572392"
}, {
"url": "hulu.com",
"isMobile": false,
"webIdString": "sad1228"
}],
"item2name": [{
"url": "apple.com",
"isMobile": true,
"webIdString": "dsy38ds"
}, {
"url": "Facebook.com",
"isMobile": true,
"webIdString": "326dsigd1"
}, {
"url": "YouTube.com",
"isMobile": true,
"webIdString": "sd3dsg4k"
}]
}
}
The json can have multiple items (such as item1name, item2name, item3name,...) and each item can have multiple objects (the example has 2 objects for the first item and 3 objects for the second item).
Here is the structure I want it saved to (incomplete):
struct ServerResponse: Decodable {
let items: [MyItem]?
}
struct MyItem: Decodable {
let itemName: String?
let url: String?
let isMobile: Bool?
let webIdString: String?
}
In the example above, it would mean that the items list should have five MyItem objects. For example, these would be the MyItem objects:
#1:
itemName: item1name,
url: google.com,
isMobile: true,
webIdString: 572392
#2:
itemName: item1name,
url: hulu.com,
isMobile: false,
webIdString: sad1228
#3:
itemName: item2name,
url: apple.com,
isMobile: true,
webIdString: dsy38ds
#4:
itemName: item2name,
url: Facebook.com,
isMobile: true,
webIdString: 326dsigd1
#5:
itemName: item2name,
url: YouTube.com,
isMobile: true,
webIdString: sd3dsg4k
What would be the best way for me to do this using Decodable? Any help would be appreciated. I think this may be similar to this problem: How to decode a nested JSON struct with Swift Decodable protocol?

Answer 1

Use below code to decode nested JSON for your requirement:
import Foundation
// MARK: - Websites
struct Websites: Codable {
var myItems: MyItems
}
// MARK: - MyItems
struct MyItems: Codable {
var item1Name, item2Name: [ItemName]
enum CodingKeys: String, CodingKey {
case item1Name = "item1name"
case item2Name = "item2name"
}
}
// MARK: - ItemName
struct ItemName: Codable {
var url: String
var isMobile: Bool
var webIDString: String
enum CodingKeys: String, CodingKey {
case url, isMobile
case webIDString = "webIdString"
}
}
NOTE: change the name of the variables according to your need.
EDIT
If you're still facing issue, use this app to convert your JSON to Struct:
Quick Type

Answer 2

Here is the structure you are after:
struct Websites: Decodable {
let items: [Item]
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: Key.self)
items = try container.decode([String: [Item]].self, forKey: .myItems).values.flatMap { $0 }
}
private enum Key: String, CodingKey {
case myItems
}
}
struct Item: Decodable {
let url: String
let isMobile: Bool
let webIdString: String
}