Unwrapping values swift

Question

So I am having some issues with unwrapping and optionals. I am using Google Places and passing the place.formattedAddress value twice...first from the GMSAutocompleteViewController to a UIView to be displayed within a string. Then I want to pass the place.formattedAddress to Firebase after the user confirms the place. I am able to pass the selected GMSPlace into the UIView, but then once I call the confirmAddPlace() function it crashes at line > let placeID2 = place.placeID and gives me the "terminating with uncaught exception of type NSException". I believe it has something to do with unwrapping and optionals...I am still somewhat new to this concept. Thanks for any and all help!

// Pass GMSPlace to UIView string
    // MARK: GOOGLE AUTO COMPLETE DELEGATE

    func viewController(_ viewController: GMSAutocompleteViewController, didAutocompleteWith place: GMSPlace) {

        let placeID = place.placeID

        placesClient.lookUpPlaceID(placeID, callback: { (place, error) -> Void in
            if let error = error {
                print("lookup place id query error: \(error.localizedDescription)")
                return
            }

            guard let place = place else {
                print("No place details for \(placeID)")
                return
            }
            print("Place name \(place.name)")
            print("Place address \(place.formattedAddress)")
        })

        let selectedPlace = place.formattedAddress
        if let name = selectedPlace as String!
        {
            self.placeNameLabel.text = "Are you sure you would like to add \(name) to your places?"
        }
        self.dismiss(animated: true, completion: nil)
        setupConfirmationPopUp()
    }

// user taps confirm button to send item to be updated in Firebase
    func confirmAddPlace(place: GMSPlace!) {

        let accessToken = FBSDKAccessToken.current()
        guard let accessTokenString = accessToken?.tokenString else { return }

        let credentials = FIRFacebookAuthProvider.credential(withAccessToken: accessTokenString)
        FIRAuth.auth()?.signIn(with: credentials, completion: { (user, error) in
            if error != nil {
                print("Something went wrong with our FB user: ", error ?? "")
                return
        }

// create place on tap pf confirm
            let placeID2 = place.placeID

            guard let place = place else {
                print("No place details for \(placeID2)")
                return
            }

            let confirmedPlace = place.formattedAddress
            if let confirmedPlace = confirmedPlace as String!
            {
                self.placeNameLabel.text = "\(confirmedPlace)"
            }

            let ref = FIRDatabase.database().reference().child("places")
            let childRef = ref.childByAutoId()
            let values = ["place": self.placeNameLabel.text, "name": user!.displayName]
            childRef.updateChildValues(values)
    })  
        animateOut()
    }

Answer 1

Don't force unwrap your parameters in func. Either you make them optional or you use them as their type.

For making optional:

func confirmAddPlace(place: GMSPlace?) {
    ...
    ...
    let placeID2 = place?.placeID
    ...
    ...
}

For using their type as is: (but for this you have to call this func with unwraped value, like: confirmAddPlace(myPlace!))

func confirmAddPlace(place: GMSPlace) {
    ...
    ...
    let placeID2 = place.placeID
    ...
    ...
}

But if you do want to stick with your implementation then you can just swap like this:

guard let place = place else {
    return
}
let placeID2 = place.placeID

This will return from your func if something is suspicious with your passed place