Can't get string data from WKUserContentController didReceive WKScriptMessage

Question

My method is called:

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    print("message.body: \(message.body)")
    
    if let messageBody = message.body as? [String: Any] {
        print("messageBody: \(messageBody)") //this is not triggered
        if let data = messageBody["data"] as? NSString {
            print("DATA: \(data)")
        }
    }

The message body is:

message.body: {"type":3,"data":"{\"title\":\"Verzamelen\",\"content\":\"Loongegevens...\"}"}

But after that I'm not able to retrieve the "data" field. What am I missing?

Answer 1

The issue was probably related to the backslash escapes in the String . What worked is decoding it with JSON decoder:

struct ScriptMessage: Codable {
    let type: Int
    let data: String
}


func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    
    guard let bodyString = message.body as? String,
          let bodyData = bodyString.data(using: .utf8) else {
        return
    }
    
    if let bodyStruct = try? JSONDecoder().decode(ScriptMessage.self, from: bodyData) {
        print(bodyStruct.data)
    }
}