URL swift extension to get query parameter values array (adapted from https://gist.github.com/InsertNetan/372c9f51549ea96e5af2)

URL+Query.swift

import Foundation

extension URL {
    func queryItemValues(key: String) -> [String?]? {
        guard let components = NSURLComponents(url: self, resolvingAgainstBaseURL: false) else {
            return nil
        }
        
        guard let queryItems = components.queryItems else { return nil }
        return queryItems.filter {
            $0.name == key
        }.map {
                $0.value
        }
    }
}