Why can't Swift recognize the array sent by JS?

Question

I am communicating with js using Webview. I transfer into parameter api the received data again. But when Swift get an array from JS, Swift don't recognize it properly.

Where to Send Data from JS

var jsonData = {
  data,
  type : "fromjs"
};
alert(jsonData)
webkit.messageHandlers.sendFromJS.postMessage(jsonData);

Data Viewed by Alerts

{
    "type" = "fromjs",
    "data" = {
            "num": "one",
            "arr_data" : [{ "title": "test1", "val" : "testval1" },
                          { "title": "test2" , "val" : "testval2"}]
           }
}

I check the data received by Swift.

@available(iOS 8.0, *)
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
   if message.name == "sendFromJS" {
        let getdata = message.body as! NSDictionary
        print(getdata)

But Swift doesn't recognize the array properly.

{
    type = "fromjs",
    data = {
            "num": "one",
            "arr_data" : ({ "title": "test1", "val" : "testval1" },
                          { "title": "test2" , "val" : "testval2"})
           }
}

Swift recognizes square brackets as parentheses.

How can you solve this problem? I have to send the data that I received by putting it in the parameters as it is.

func apiCall(_ param: NSDictionary){
   let parameters: [String: AnyObject] = param["data"] as! [String : AnyObject]
Alamofire.request(url, method: .post, parameters: parameters, encoding: URLEncoding.default, headers: headers)

I've changed the type of data. But it's equally unrecognizable.

let getdata = message.body as! [String : Any]
 print(getdata)

//log
[
    type = "fromjs",
    data = {
            "num": "one",
            "arr_data" : ({ "title": "test1", "val" : "testval1" },
                          { "title": "test2" , "val" : "testval2"})
           }
]

To create json data in js

var data = {
  num: "one"
};
var data_arr = [];
data_arr.push({"title": "test1", "val" : "testval1"});
data_arr.push({"title": "test2" , "val" : "testval2"});
data.arr_data = data_arr;
var jsonData = {
  data,
  type : "fromjs"
};
alert(jsonData)
webkit.messageHandlers.sendFromJS.postMessage(jsonData);

@FahriAzimov I wrote down the data shown in the Swift log in the question. Is this correct? So why doesn't the parameters have an array? — hong developer
– hong developer, Commented Nov 15, 2019 at 1:18
Yes, it's correct, because you are printing the NSDictionary, if you print Swift dictionary, it will have square brackets ) — Fahri Azimov
– Fahri Azimov, Commented Nov 15, 2019 at 1:22
Anyways, don't use Objective C types with Swift, it has it's own types, for the dictionary, it has Dictionary, or you can directly use [String: Any] as type and it will be a dictionary. — Fahri Azimov
– Fahri Azimov, Commented Nov 15, 2019 at 1:24
@FahriAzimov Do you mean to change the parameter type of the function to [String: Any]? — hong developer
– hong developer, Commented Nov 15, 2019 at 1:33

hong developer · Accepted Answer · 2019-11-18 06:42:58Z

1

This is just a difference in the way that JSON and traditional NeXT property lists represent arrays.

Example

let json = """{ "a": [1, 2, 3] }"""
let jsonData = try! JSONSerialization.jsonObject(with: Data(json.utf8), options: [])
print("plist:", jsonData)
let jsonString = try! JSONSerialization.data(withJSONObject: d, options: [.prettyPrinted])
print("json:", String(data: jsonString, encoding: .utf8)!)

Print Log

plist: {
    a =     (
        1,
        2,
        3
    );
}
json: {
  "a" : [
    1,
    2,
    3
  ]
}

The property list renders the array using ( … ) but that’s just a rendering oddity. The actual objects are correct, as witnessed by the fact that I can turn them back into the some JSON I started with.

answered Nov 18, 2019 at 6:42

hong developer

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