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Setting Up the Stack

This video was last updated on Jul 19 2022

Create a Core Data stack for use in the RocketLaunches app!


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Now that you have a better understanding of the moving parts let’s actually write some code.

import CoreData
struct PersistenceController {

struct PersistenceController {
  static let shared = PersistenceController()

  static var preview: PersistenceController = {
    let result = PersistenceController(inMemory: true)
    let viewContext = result.container.viewContext
    // Dummy data will go here later
    do {
    } catch {
      let nsError = error as NSError
      fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
    return result
  let container: NSPersistentContainer

  init(inMemory: Bool = false) {

let container = NSPersistentContainer
container = NSPersistentContainer(name: "RocketLaunches")
if inMemory {
  // swiftlint:disable:next force_unwrapping
  container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
container.loadPersistentStores { _, error in }
if let error = error as NSError? {
  fatalError("Unresolved error \(error), \(error.userInfo)")
  container.viewContext.automaticallyMergesChangesFromParent =
    true = "viewContext"
  /// - Tag: viewContextMergePolicy
  container.viewContext.mergePolicy = 
  container.viewContext.undoManager = nil
  container.viewContext.shouldDeleteInaccessibleFaults = true