awsiot-3.js

func getAWSClientID(completion: @escaping (_ clientId: String?,_ error: Error? ) -> Void) {
        // Depending on your scope you may still have access to the original credentials var
        let credentials = AWSCognitoCredentialsProvider(regionType:.EUWest1, identityPoolId: "your-identity-pool-id")
        
        credentials.getIdentityId().continueWith(block: { (task:AWSTask<NSString>) -> Any? in
            if let error = task.error as NSError? {
                print("Failed to get client ID => \(error)")
                completion(nil, error)
                return nil  // Required by AWSTask closure
            }
            
            let clientId = task.result! as String
            print("Got client ID => \(clientId)")
            completion(clientId, nil)
            return nil // Required by AWSTask closure
        })
    }