How to convert dictionary to json string without space and new line

Question

I am trying to convert a dictionary to json string without space and new line. I tried to use JSONSerialization.jsonObject but I still can see spaces and new lines. Is there any way to have a string result looks something like this

"data": "{\"requests\":[{\"image\":{\"source\":{\"imageUri\":\"https://www.google.com/images/branding/googlelogo/2x/googlelogo_color_272x92dp.png\"}},\"features\":[{\"type\":\"LOGO_DETECTION\",\"maxResults\":1}]}]}"

My conversion

var features = [[String: String]]()
for detection in detections {
    features.append(["type": imageDetection[detection]!])
}
let content = ["content": base64Image]
let request = ["image": content, "features": features] as [String : Any]
let requests = ["requests": [request]]

let jsonData = try! JSONSerialization.data(withJSONObject: requests, options: .prettyPrinted)
let decoded = try! JSONSerialization.jsonObject(with: jsonData, options: [])
print(decoded)

Result

{
    requests =     (
                {
            features =             (
                                {
                    type = "LABEL_DETECTION";
                },
                                {
                    type = "WEB_DETECTION";
                },
                                {
                    type = "TEXT_DETECTION";
                }
            );
            image =             {
                content = "iVBO
      ...........

Answer 1

You are decoding the serialized JSON into an object. When an object is printed into the console, you will see the indentation, and the use of equals symbols and parentheses.

Remove the .prettyPrinted option and use the data to initialize a string with .utf8 encoding.

let jsonData = try! JSONSerialization.data(withJSONObject: requests, options: [])
let decoded = String(data: jsonData!, encoding: .utf8)!