Creates JSON representation from the swift struct. Code was copied from this blog, all the credit goes to the original author of the blog http://codelle.com/blog/2016/5/an-easy-way-to-convert-swift-structs-to-json/

StructToJSON.swift

protocol JSONRepresentable {
    var JSONRepresentation: Any { get }
}

protocol JSONSerializable: JSONRepresentable {
    
}

extension JSONSerializable {
    var JSONRepresentation: Any {
        var representation = [String: Any]()
        
        for case let (label?, value) in Mirror(reflecting: self).children {
            switch value {
            case let value as JSONRepresentable:
                representation[label] = value.JSONRepresentation
                
            case let value as NSObject:
                representation[label] = value
                
            default:
                // Ignore any unserializable properties
                break
            }
        }
        
        return representation
    }
}

extension JSONSerializable {
    func toJSON() -> String? {
        let representation = JSONRepresentation
        
        guard JSONSerialization.isValidJSONObject(representation) else {
            return nil
        }
        
        do {
            let data = try JSONSerialization.data(withJSONObject: representation, options: [])
            return String(data: data, encoding: String.Encoding.utf8)
        } catch {
            return nil
        }
    }
}

extension Date: JSONRepresentable {
    var JSONRepresentation: Any {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS"
        
        return formatter.string(from: self)
    }
}

StructToJSONDemo.swift

struct Event: JSONSerializable {
    var name: String
    var timestamp: NSDate
}

let event = Event(name: "Something happened", timestamp: NSDate())

if let json = event.toJSON() {
    print(json)
}