extension String {

    func toJSON() -> Any? {

        guard let data = self.data(using: .utf8, allowLossyConversion: false) else { return nil }

        return try? JSONSerialization.jsonObject(with: data, options: .mutableContainers)

    }

}

do{  

let json = try JSONSerialization.jsonObject(with: data!, options: []) as? [String : Any]

}catch{ print("erroMsg") }

  let jsonText = "{\"first_name\":\"Sergey\"}"

        var dictonary:NSDictionary?

        if let data = jsonText.data(using: String.Encoding.utf8) {

            do {

                dictonary = try JSONSerialization.jsonObject(with: data, options: []) as? [String:AnyObject]

                if let myDictionary = dictonary

                {

                     print(" First name is: \(myDictionary["first_name"]!)")

                }

            } catch let error as NSError {

                print(error)

            }

        }

func jsonToString(json: AnyObject){

        do {

          let data1 =  try NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions.PrettyPrinted) // first of all convert json to the data

            let convertedString = String(data: data1, encoding: NSUTF8StringEncoding) // the data will be converted to the string

            print(convertedString) // <-- here is ur string  

​

        } catch let myJSONError {

            print(myJSONError)

        }

​

    }

// for encoing your model or sturct must inherit codable protocol

var general = [str: products]

let encodedData = try? JSONEncoder().encode(general)

struct MyStruct: Decodable {

    let myProperty: String

    // Add more properties as needed

}

​

let jsonString = """

{

    "myProperty": "Hello, World!"

}

"""

​

let jsonData = jsonString.data(using: .utf8)!

​

do {

    let decodedObject = try JSONDecoder().decode(MyStruct.self, from: jsonData)

    print(decodedObject.myProperty) // Output: Hello, World!

} catch {

    print("Error decoding JSON: \(error)")

}

let sentences = [Sentence(sentence: "Hello world", lang: "sd"), 

                 Sentence(sentence: "Hallo Welt", lang: "de")]

func jsonToString(json: AnyObject){

        do {

          let data1 =  try NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions.PrettyPrinted) // first of all convert json to the data

            let convertedString = String(data: data1, encoding: NSUTF8StringEncoding) // the data will be converted to the string

            print(convertedString) // <-- here is ur string  

​

        } catch let myJSONError {

            print(myJSONError)

        }

​

    }