Get JSON String from a Dictionary

gistfile1.txt

extension Dictionary {
    var json: String {
        let invalidJson = "Error: Invalid JSON"
        do {
            let jsonData = try JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
            return String(bytes: jsonData, encoding: String.Encoding.utf8) ?? invalidJson
        } catch {
            return invalidJson
        }
    }
    
    func getJSONString() -> String {
        return json
    }
}