NSURL swift extension that parses URL query string into [String: AnyObject] dictionary, using NSURLComponents and supporting array for values that uses ',' to separate array items

NSURL+QueryDictionary.swift

extension NSURL {
    var queryDictionary: [String: AnyObject]? {
        return NSURLComponents(URL: self, resolvingAgainstBaseURL: false)?
            .queryItems?
            .reduce([:], combine: { (var result: [String: AnyObject], queryItem) -> [String: AnyObject] in
                if queryItem.value?.containsString(",") ?? false {
                    let array = queryItem.value?.componentsSeparatedByString(",")
                    
                    result[queryItem.name] = array
                }
                else {
                    result[queryItem.name] = queryItem.value
                }
                
                return result
            })
    }
}