return and exit from compactMap - swift

Question

I am checking some dynamic texts with Regex Rules, using switch for each index of regex pattern array. everything is working fine but in the last case i want the map to stop mapping and do an early return! but seems like i can't return inside a map function! any better approach or solution ?
fileprivate func regexMatch(pattern regex: [String], in text: String) -> Dictionary<String, Any>
{
do
{
for (index, string) in regex.enumerated()
{
let regex = try NSRegularExpression(pattern: string, options: .caseInsensitive)
let results: [NSTextCheckingResult] = regex.matches(in: text, range: NSRange(text.startIndex..., in: text))
_ = results.compactMap
{
/* If i put a guard check to see if result is filled
* then return, works fine but iterates again for the next index and keeps returning till it’s over!
*/
switch index
{
case 0:
// Does something
case 1:
// Does something else
case 2:
// Does the last thing
// If succeed finding the match! Just return or exit the map!
let carNames = String(Range($0.range, in: text).map { String(text[$0]) }!).lowercased()
for case let car as Car in carsList!
{
if spottedCarNamesInReceipt.contains(car.name!.lowercased())
{
result["car"] = car
return // This does work though, but the map starts iterating again over the next index!
}
}
default:
break;
}
}
}
return result
} catch let error
{
print("Invalid regex: \(error.localizedDescription)")
return [:]
}

Answer 1

You don't need to use compactMap if you don't use results. And there is no way to exit from compactMap. Use for in cycle.

Answer 2

Using return statement forEach loop or any kind of Maps, exits only for the current call in the closure while for...in loop exits all the next subsequent calls as well. so for...in solves the problem if an early exit is needed.