Swift generic functions issues. Decrease duplicating code - ios

Question

I want to understand how can decrease amount of duplicated code. I have two almost the same functions. The differences are next:
firs function returns array of [ExerciseEntity] and second function returns array of [WorkoutEntity]
func replaceExercisesIdentifiers(from jsonObjects: [[String: Any]], transaction: BaseDataTransaction) -> [ExerciseEntity] {
for jsonObject in jsonObjects {
if let mobileLocalId = jsonObject["mobileLocalId"] as? String {
if mobileLocalId.contains("<x-coredata://") {
if let managedObject = try? transaction.fetchOne(From<ExerciseEntity>()
.where(
format: "%K == %#",
#keyPath(BaseMO.id),
mobileLocalId)
) {
let editObject = transaction.edit(managedObject)
if let identifier = jsonObject["id"] as? String {
editObject?.id = identifier
}
}
}
}
}
let managedObjects = try! transaction.importUniqueObjects(
Into<ExerciseEntity>(),
sourceArray: jsonObjects)
return managedObjects
}
func replaceWorkoutsIdentifiers(from jsonObjects: [[String: Any]], transaction: BaseDataTransaction) -> [WorkoutEntity] {
for jsonObject in jsonObjects {
if let mobileLocalId = jsonObject["mobileLocalId"] as? String {
if mobileLocalId.contains("<x-coredata://") {
if let managedObject = try? transaction.fetchOne(From<WorkoutEntity>()
.where(
format: "%K == %#",
#keyPath(BaseMO.id),
mobileLocalId)
) {
let editObject = transaction.edit(managedObject)
if let identifier = jsonObject["id"] as? String {
editObject?.id = identifier
}
}
}
}
}
let managedObjects = try! transaction.importUniqueObjects(
Into<WorkoutEntity>(),
sourceArray: jsonObjects)
return managedObjects
}
This is a similar question related to how to use generic function I asked before.
I implemented this in my code but:
func importArray<T: ImportableUniqueObject>(from exercisesDict: [[String: Any]], transaction: BaseDataTransaction) -> [T] where T.ImportSource == [String: Any] {
let managedObjects = try? transaction.importUniqueObjects(Into<T>(), sourceArray: jsonObjects)
}
But here is few things, with T type
First - I can't add this code: editObject?.id = identifier
as there is no id in T type.
Second when I debug these generic functions debugger every time crashes:
Message from debugger: The LLDB RPC server has crashed. The crash log is located in ~/Library/Logs/DiagnosticReports and has a prefix 'lldb-rpc-server'. Please file a bug and attach the most recent crash log.
If interesting here is a file with log. I have not submitted it yet.
For sure I can add a lot of prints to track behavior, though it's a but annoying) But main task is to get rid of duplication.

Answer 1

Try this (I have not tested):
protocol MyProtocol {
var id: Int { get set }
}
struct ExerciseEntity {
var id: Int
}
struct WorkoutEntity {
var id: Int
}
func replaceWorkoutsIdentifiers<T: MyProtocol>(from jsonObjects: [[String: Any]], transaction: BaseDataTransaction) -> [T] {
for jsonObject in jsonObjects {
if let mobileLocalId = jsonObject["mobileLocalId"] as? String {
if mobileLocalId.contains("<x-coredata://") {
if let managedObject = try? transaction.fetchOne(From<T>()
.where(
format: "%K == %#",
#keyPath(BaseMO.id),
mobileLocalId)
) {
let editObject = transaction.edit(managedObject)
if let identifier = jsonObject["id"] as? String {
editObject?.id = identifier
}
}
}
}
}
let managedObjects = try! transaction.importUniqueObjects(
Into<T>(),
sourceArray: jsonObjects)
return managedObjects as! T
}
Using:
let array: [ExerciseEntity] = replaceWorkoutsIdentifiers(from jsonObjects: ..., transaction: ...)