Thread 4: Fatal error: 'try!' expression unexpectedly raised an error - json

Question

I'm trying to learn to make an API call in swiftUI, I'm following the next tutorial https://www.youtube.com/watch?v=1en4JyW3XSI but the code is giving me an error that I can't find a solution for.
PostList.swift
import SwiftUI
struct PostList: View {
#State var posts: [Post] = []
var body: some View {
List(posts) { post in
Text(post.title)
}
.onAppear(){
Api().getPosts { (posts) in
self.posts = posts
}
}
}
}
struct PostList_Previews: PreviewProvider {
static var previews: some View {
PostList()
}
}
Data.swift
import SwiftUI
struct Post: Codable, Identifiable {
var id = UUID()
var title: String
var body: String
}
class Api{
func getPosts(completition: #escaping([Post]) -> ()){
guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else { return }
URLSession.shared.dataTask(with: url) { (data, _, _) in
let posts = try! JSONDecoder().decode([Post].self, from: data!)
DispatchQueue.main.async {
completition(posts)
}
}
.resume()
}
}
The error that I'm getting is on here let posts = try! JSONDecoder().decode([Post].self, from: data!) and it's the next:
Thread 4: Fatal error: 'try!' expression unexpectedly raised an error:
Swift.DecodingError.typeMismatch(Swift.String,
Swift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "Index
0", intValue: 0), CodingKeys(stringValue: "id", intValue: nil)],
debugDescription: "Expected to decode String but found a number
instead.", underlyingError: nil))
I have noticed that the guy in the tutorial uses let id = UUID() but that gives me a problem as well and I'm being asked to change it to var id = UUID().
I'm sorry if it's a very simple or stupid question, I just can't see to find a way around it.

Answer 1

You can see the exact problem by adding try - catch block for the exact error.
Like this
URLSession.shared.dataTask(with: url) { (data, _, _) in
do {
let posts = try JSONDecoder().decode([Post].self, from: data!)
DispatchQueue.main.async {
completition(posts)
}
} catch {
print(error.localizedDescription)
}
}
So now the error is printed:
The data couldn’t be read because it isn’t in the correct format.
It means you are decoding the wrong type.
The problem is here
struct Post: Codable, Identifiable {
var id = UUID() //< Here
Here in json id have Int type and you are using UUID type.
So just change the data type UUID to Int. Like this
struct Post: Codable, Identifiable {
var id : Int //< Here