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 From Swift

[

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);

Swift

2.4k

Posted by

beginerIOS

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Answer 1

Swift recognizes square brackets as parentheses.

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

let json = """
    { "a": [1, 2, 3] }
    """
let d = try! JSONSerialization.jsonObject(with: Data(json.utf8), options: [])
print("plist:", d)
let d2 = try! JSONSerialization.data(withJSONObject: d, options: [.prettyPrinted])
print("json:", String(data: d2, encoding: .utf8)!)

It prints:

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 you can turn them back into the some JSON you started with.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Posted by

eskimo

Add a Comment

Answer 2

Did you try replacing

func apiCall(_ param: NSDictionary) {

by

func apiCall(_ param: Dictionary) {

Posted by

Claude31

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Answer 3

I tried change value But get error

func apiCall(_ param: Dictionary) {

Reference to generic type 'Dictionary' requires arguments in

Insert '<<#Key: Hashable#>, Any>'

Posted by

beginerIOS

Add a Comment

Answer 4

Where exactly in code do you get the error ?

Posted by

Claude31

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Answer 5

Just like the code you wrote in your answer, I changed my code the same way, and I got the following error.

Reference to generic type 'Dictionary' requires arguments in

Insert '<<#Key: Hashable#>, Any>'

Click the fix button to change:

Dictionary<<#Key: Hashable#>, Any>

When creating a Dictionary, it appears that I must specify a type by default.

Dictionary Example

var dic : [Int : String] = [:]
var dic2 = [Int : String]()
var dic3 : Dictionary = [Int:String]()
var dic4 : Dictionary<int, string=""> = Dictionary<int, string="">()

But as you can see from my question, this is how I've already tried.

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

Posted by

beginerIOS

Add a Comment

Answer 6

Did you try using decodable ?

https://stackoverflow.com/questions/42081141/how-to-parse-array-of-json-to-array-in-swift/42081743

Posted by

Claude31

Add a Comment

Answer 7

Swift recognizes square brackets as parentheses.

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

let json = """
    { "a": [1, 2, 3] }
    """
let d = try! JSONSerialization.jsonObject(with: Data(json.utf8), options: [])
print("plist:", d)
let d2 = try! JSONSerialization.data(withJSONObject: d, options: [.prettyPrinted])
print("json:", String(data: d2, encoding: .utf8)!)

It prints:

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 you can turn them back into the some JSON you started with.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Posted by

eskimo

Add a Comment

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

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