Looping through JSON array | Swift 5 - swift

Question

I need to perform an action on each instance of trialid in the following JSON array - How can I loop through each instance of trialid using forEach? The goal is to pass each instance of trialid to another function that only excepts one value of trialid at a time.
The following is the structure of the JSON array:
[
{
"name": "mobile",
"orderid": 1,
"trialid": 27
},
{
"name": "mobile",
"orderid": 1,
"trialid": 33
}
]
The following is the what I am currently trying - how can foreach be performed here to loop through each object:
var structure = [testStructure]()
func fetch() {
guard let url = URL(string: "test.com")
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = "id=1".data(using: .utf8)
URLSession.shared.dataTask(with: request) { data, _, error in
guard let data = data else { return }
do {
let nav = try JSONDecoder().decode(structure, from: data)
structure.forEach ..
}
catch {
print(error)
}
}.resume()
}
struct testStructure: Decodable {
let name: String?
let orderid: Int?
let trialid: Int?
}

Answer 1

First of all please start names of classes, structures and other types with a capital letter.
If the API JSON response contains an array you need to decode it to the array type like this:
let nav = try JSONDecoder().decode([TestStructure].self, from: data)
then you can iterate through your decoded array of structures (full code):
import UIKit
struct TestStructure: Decodable {
let name: String?
let orderid: Int?
let trialid: Int?
}
func fetch() {
guard let url = URL(string: "test.com")
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = "id=1".data(using: .utf8)
URLSession.shared.dataTask(with: request) { data, _, error in
guard let data = data else { return }
do {
let nav = try JSONDecoder().decode([TestStructure].self, from: data)
nav.forEach { testStructure in
// do whatever you want here
if let trialid = testStructure.trialid {
processingTrialid(trialid)
}
}
}
catch {
print(error)
}
}.resume()
}
func processingTrialid(_ trialid: Int) {
print("trialid: ", trialid)
}