keremk

func fetchPreviewData<T: Decodable>(previewFile: String, fetcher: () -> T) -> T {
#if PREVIEW
    return loadPreviewData(previewFile)
#else
    return fetcher()
#endif
}

#if PREVIEW
// Below is directly "borrowed" from https://developer.apple.com/tutorials/swiftui/composing-complex-interfaces

keremk

import Foundation
import UIKit

func fetchPreviewImage(imageName: String, size: ImageSizeable, fetcher: () -> CGImage?) -> CGImage? {
#if PREVIEW
    return loadPreviewImage(name: imageName, size: size)
#else
    return fetcher()
#endif
}

keremk

func fetchPreviewImage(imageName: String, size: ImageSizeable, fetcher: () -> CGImage?) -> CGImage? {
#if PREVIEW
    return loadPreviewImage(name: imageName, size: size)
#else
    return fetcher()
#endif
}

keremk

import Foundation
import Combine

final class MovieCollection: ObservableObject {
    @Published var movieResponse: MovieResponse? = nil

    ...
    
    func fetchMovies() -> [Movie] {
        let response: MovieResponse? = fetchPreviewData(previewFile: "movies.json", fetcher: fetchResponse)

keremk

{
    "page": 2,
    "total_results": 10000,
    "total_pages": 500,
    "results": [
        {
            "popularity": 74.704,
            "vote_count": 9537,
            "video": false,
            "poster_path": "\/kOVEVeg59E0wsnXmF9nrh6OmWII.jpg",

keremk

struct MovieRow: View {
    var movie: Movie
    
    var body: some View {
        HStack {
            MoviePoster(imageName: movie.posterName)
                .frame(width: 97.5, height: 146.25, alignment: Alignment.center)
                
            VStack(alignment: .leading) {
             ...

keremk

final class ImageResolver: ObservableObject {
    @Published var image: CGImage? = nil

    ...    
    
    func fetchImage() -> CGImage? {
        return fetchPreviewImage(imageName: name, size: size, fetcher: fetch)
    }

    private func fetch() -> CGImage? {

keremk

import SwiftUI

struct MoviePoster: View {
    let imageName: String
    let placeholder = UIImage(named: "placeholder.jpg")!.cgImage!
    
    @ObservedObject private var resolver: ImageResolver
    
    init(imageName: String) {
        self.imageName = imageName

keremk

#if DEBUG
struct MovieList_Previews: PreviewProvider {
    static var previews: some View {
        let movies = MovieCollection().fetchMovies()
        let selectMovies = [movies[0], movies[2], movies[3]]
        return MovieList(movies: selectMovies)
            .previewLayout(.sizeThatFits)
            .environmentObject(EnvironmentConfig(mode: .PreviewMode))
    }
}

keremk

// Playground - noun: a place where people can play

import UIKit

var str = "Hello, playground"

enum TimeIntervalUnit {
  case Seconds, Minutes, Hours, Days, Months, Years
  
  func dateComponents(interval: Int) -> NSDateComponents {