asyncimages.swift

final class Loader: BindableObject {
    let didChange = PassthroughSubject<Data?, Never>()
    var task: URLSessionDataTask!
    var data: Data? = nil {
        didSet {
            didChange.send(data)
        }
    }
    
    init(_ url: URL) {
        task = URLSession.shared.dataTask(with: url, completionHandler: { data, _, _ in
            DispatchQueue.main.async {
                self.data = data
            }
        })
        task.resume()
    }
    deinit {
        task.cancel()
    }
}

let placeholder = UIImage(named: "placeholder.jpg")!
struct MyView: View {
    init(url: URL) {
        self.imageLoader = Loader(url)
    }
    @ObjectBinding private var imageLoader: Loader
    var image: UIImage? {
        imageLoader.data.flatMap(UIImage.init)
    }
    
    
    var body: some View {
        Image(uiImage: image ?? placeholder)
    }
}

How would you go and make this change animate in ?

I haven't gotten to try SwiftUI myself, but I think I remember an example from a session to animate a change:

    var body: some View {
        withAnimation { Image(uiImage: image ?? placeholder) }
    }

That code make Xcode unable to build my project or Segmentation fault occurs

Update code for newest (when @BindableObject has been depreciated):

import SwiftUI

final class Loader: ObservableObject {
    
    var task: URLSessionDataTask!
    @Published var data: Data? = nil
    
    init(_ url: URL) {
        task = URLSession.shared.dataTask(with: url, completionHandler: { data, _, _ in
            DispatchQueue.main.async {
                self.data = data
            }
        })
        task.resume()
    }
    deinit {
        task.cancel()
    }
}

let placeholder = UIImage(named: "placeholder.jpg")!

struct AsyncImage: View {
    init(url: URL) {
        self.imageLoader = Loader(url)
    }
    
    @ObservedObject private var imageLoader: Loader
    var image: UIImage? {
        imageLoader.data.flatMap(UIImage.init)
    }
    
    
    var body: some View {
        Image(uiImage: image ?? placeholder)
    }
}

Thanks man this was really useful :)