iOS: Delete ALL Core Data Swift

Question

I am a little confused as to how to delete all core data in swift. I have created a button with an IBAction linked. On the click of the button I have the follow

Answer 1

This clean() method will fetch entities list from DataModel and clear all data.

func deleteAll(entityName: String) -> Error? {
            if #available(iOS 9.0, *) {
                do {
                    let fetchRequest = NSFetchRequest(entityName: entityName)
                    let batchDeleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
                    try context.execute(batchDeleteRequest)
                } catch {
                    return error
                }
                return nil
            } else {
                let fetchRequest = NSFetchRequest(entityName: entityName)
                fetchRequest.returnsObjectsAsFaults = false
                do
                {
                    let results = try context.fetch(fetchRequest)
                    for managedObject in results
                    {
                        if let managedObjectData:NSManagedObject = managedObject as? NSManagedObject {
                            context.delete(managedObjectData)
                        }
                    }
                } catch  {
                    return error
                }
                return nil
            }
        }

        var objectModel: NSManagedObjectModel? {
            if #available(iOS 10.0, *) {
                return persistentContainer.managedObjectModel
            } else {
                return persistentStoreCoordinator?.managedObjectModel
            }
        }

        open func clean() {
            if let models = objectModel?.entities {
                for entity in models {
                    if let entityName = entity.name {
                        _ = deleteAll(entityName: entityName)
                    }
                }
            }
        }

Happy Coding!