import Foundation

extension Data {
    var prettyPrintedJSONString: NSString? { /// NSString gives us a nice sanitized debugDescription
        guard let object = try? JSONSerialization.jsonObject(with: self, options: []),
              let data = try? JSONSerialization.data(withJSONObject: object, options: [.prettyPrinted]),
              let prettyPrintedString = NSString(data: data, encoding: String.Encoding.utf8.rawValue) else { return nil }

        return prettyPrintedString
    }
}

let str = "{\"foo\": \"bar\"}".data(using: .utf8)!.prettyPrintedJSONString!
debugPrint(str)
/* prints:
 {
    "foo" : "bar"
 }
*/