CoreData - Duplicate existing object

Question

Hi would like to duplicate an object from my core data db. Right now I\'m using

        movement2 = [NSEntityDescription
                                     ins         


        

Answer 1

I've made a rudimentary duplicate extension for NSManagedObject (based on @coverback's answer). Use with care (though for me it works so far)

Swift 4:

enum CopyBehavior {
    case none, copy, deepcopy
}

extension NSManagedObject {
    func duplicate(only: [String]) -> NSManagedObject {
        return duplicate { only.contains($0) ? .copy : .none }
    }

    func duplicate(except: [String], deep: [String] = []) -> NSManagedObject {
        return duplicate { deep.contains($0) ? .deepcopy : except.contains($0) ? .none : .copy }
    }

    func duplicate(byProperties fun: (String) -> CopyBehavior) -> NSManagedObject {
        let duplicate = NSEntityDescription.insertNewObject(forEntityName: entity.name!, into: managedObjectContext!)

        for propertyName in entity.propertiesByName.keys {
            switch fun(propertyName) {
            case .copy:
                let value = self.value(forKey: propertyName)
                duplicate.setValue(value, forKey: propertyName)
            case .deepcopy:
                let value = self.value(forKey: propertyName)
                if let value = value as? NSSet {
                    let copy = value.map {
                        return ($0 as! NSManagedObject).duplicate(byProperties: fun)
                    }
                    duplicate.setValue(copy, forKey: propertyName)
                }
                else if let value = value as? NSOrderedSet {
                    let copy = value.map {
                        return ($0 as! NSManagedObject).duplicate(byProperties: fun)
                    }
                    duplicate.setValue(NSOrderedSet(array: copy), forKey: propertyName)
                }
                else if let value = value as? NSManagedObject {
                    let copy = value.duplicate(byProperties: fun)
                    duplicate.setValue(copy, forKey: propertyName)
                }
                else {
                    fatalError("Unrecognized deepcopy attribute!")
                }
            case .none:
                break
            }
        }

        return duplicate
    }
}