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Parse return value from $ajax call in JavaScript from MVC Controller

I'm using VS2022 with C# and I'm trying to use an $ajax get method in my JavaScript function. I'm sending a parameter and returning a string[] list but when I receive the return I use JSON.stringify but when I try to use JSON.Parse it fails. The Javascript code is
$.ajax({
type: "GET",
url: '/Home/GetCategories/',
contentType: 'application/json',
datatype: 'json',
data: { ctgData: JSON.stringify(relvalue)}
}).done(function(result) {
let userObj = JSON.stringify(result);
let resultList = JSON.parse(userObj);
});
The code in the controller which returns the list is simple at the moment until I get the return working
[HttpGet]
public ActionResult GetCategories(string ctgData)
{
string[] categoryList = { "Food & Drink", "Sport & Fitness", "Education", "Housework", "Fiction", "Horror Books", "Fantasy", "Magic" };
return Json(new { data = categoryList });
}
The value in result is
{"data":["Food & Drink","Sport & Fitness","Education","Housework","Fiction","Horror Books","Fantasy","Magic"]}
I've tried a number of different ways in Parse but it always fails, can you tell me what I'm missing to get my resultList to contain the string array.

You don' t need to parse anything. It is already java script object
$.ajax({
type: "GET",
url: '/Home/GetCategories/',
contentType: 'application/json',
datatype: 'json',
data: { ctgData: JSON.stringify(relvalue)}
sucess: function(result) {
let data=result.data; // data = ["Food & Drink","Sport & Fitness",..]
}
});

use this:
JSON.parse(JSON.stringify(data))
const data = {"data":["Food & Drink","Sport & Fitness","Education","Housework","Fiction","Horror Books","Fantasy","Magic"]}
const resultJSON = JSON.parse(JSON.stringify(data))
console.log("json >>>", resultJSON)

Calling [HTTPPost] from Javascript ASP.NET

I am using a method in my controller which imports data from an API. This method I am wanted to be called from two locations. First the view (currently working) and secondly a javascript function.
Start of controller method:
[ActionName("ImportRosters")]
[HttpPost]
public ActionResult PerformImportRosterData(int id, int? actualLength, int? rosterLength)
{
var authenticator = Authenticator(id);
var rosters = authenticator.Api().RosterData().ToDictionary(x => x.Id);
var databaseRosterDatas = SiteDatabase.DeputyRosterData.Where(x => x.SiteID == id)
.ToDictionary(x => x.Id);
Javascript Function:
$("#btnDeputyRunNowUpdate").click(function() {
$("#btnRunDeputyNow").modal("hide");
ActualLength = $("#actualRunLength").val();
RosterLength = $("#rosterRunLength").val();
$.ajax({
type: "POST",
url: "/deputy/PerformImportRosterData",
data: { SiteIDRoster, ActualLength, RosterLength }
});
SiteIDRoster = null;
location.reload();
$("#btnRunDeputyNow").modal("hide");
toast.show("Import Successful", 3000);
});
All values are being set but i am getting a 404 error on the url line
POST https://example.org/deputy/PerformImportRosterData 404 ()
I need a way to be able to call this c# method from both html and JS

This can be done if you will modify the URL in your AJAX. It should look something like
url: '<%= Url.Action("YourActionName", "YourControllerName") %>'
or
url: #Url.Action("YourActionName", "YourControllerName")
one more thing, I don't see if you do anything with the result of the call. your script does not have success part
success: function(data) {//do something with the return}
and would be very helpful to have error handler in your call.
full example on how AJAX should look like:
$.ajax({
url: "target.aspx",
type: "GET",
dataType: "html",
success: function (data, status, jqXHR) {
$("#container").html(data);
alert("Local success callback.");
},
error: function (jqXHR, status, err) {
alert("Local error callback.");
},
complete: function (jqXHR, status) {
alert("Local completion callback.");
}
})
For a good tutorial on AJAX read this document
Change after Comment:
my current code is below:
$("#btnDeputyRunNowUpdate").click(function() {
$("#btnRunDeputyNow").modal("hide");
ActualLength = $("#actualRunLength").val();
RosterLength = $("#rosterRunLength").val();
$.ajax({
type: "POST",
url: '<%= Url.Action("PerformImportRosterData", "DeputyController") %>',
data: { SiteIDRoster, ActualLength, RosterLength },
success: function(data) {
console.log(data);
console.log("TESTHERE");
}
});
}
UPDATE:
Noticed one more thing. Your parameters in the controller and AJAX do not match. Please try to replace your a few lines in your AJAX call with:
url: "/deputy/PerformImportRosterData",
data: { id: yourIDValue, actualLength: youractualLengthValue,
rosterLength :yourrosterLengthValue }
remember to set all variable values in javascript , if they have no values set them = to null.
Can you try copy paste code below
$.ajax({
type: "POST",
url: "/deputy/PerformImportRosterData",
data: { SiteIDRoster:999, ActualLength:1, RosterLength:2 }
});
And let me know if it wall cause any errors.

After attempting to solve for a few days, I created a workaround by creating two methods for importing the data. one for the httpPost and the second for import calling from javascript.
Not a great solution but it works. Thanks for your help Yuri

How to use element name when initializing object in javascript?

I'm trying to get data using ajax function, but my code returns :
Uncaught SyntaxError: unexpected string..
Javascript :
var myParams = {
$('#csrf').attr('name') : $('#csrf').val(),
'module' : 'culinary',
'id' : '12',
}
$.ajax({
url: '/uploader/get_list',
type: 'GET',
data: myParams,
success: function(response) {
reponse = $.parseJSON(response);
console.log(response);
}
});
One of my friends suggested to use this:
var myParams = [];
myParams[$('#csrf').attr('name')] = $('#csrf').val();
myParams['module'] = 'culinary';
myParams['id'] = '12';
But if I use the second method, the PHP function can't recognize the parameters.
What's the correct way to send parameters to an ajax function?

The issue is in your creation of the myParams object. To create a key using a variable you need to use bracket notation. Try this:
var myParams = {
'module': 'culinary',
'id': '12',
}
myParams[$('#csrf').attr('name')] = $('#csrf').val();
The second example you have doesn't work because you create an array, ie. [], not an object, {}.
Also note that if you set the dataType property of the request then you don't need to manually parse the response as jQuery will do it for you:
$.ajax({
url: '/uploader/get_list',
type: 'GET',
data: myParams,
dataType: 'json',
success: function(response) {
console.log(response);
}
});

You should define new object {} and not new array [] :
var myParams = [];
Should be :
var myParams = {};
Hope this helps.

Sending JS array via AJAX to laravel not working

I have a javascript array which I want to send to a controller via an ajax get method.
My javascript looks like this:
var requestData = JSON.stringify(commentsArray);
console.log(requestData);
//logs correct json object
var request;
request = $.ajax({
url: "/api/comments",
method: "GET",
dataType: "json",
data: requestData
});
I can tell that my requestData is good because I am logging it and it looks right.
and the controller is being accessed correctly (i know this because I can log info there and I can return a response which I can log in my view after the response is returned).
when trying to access requestData I am getting an empty array.
My controller function that is called looks like:
public function index(Request $request)
{
Log::info($request);
//returns array (
//)
//i.e. an empty array
Log::info($request->input);
//returns ""
Log::info($_GET['data']);
//returns error with message 'Undefined index: data '
Log::info(Input::all());
//returns empty array
return Response::json(\App\Comment::get());
}
And I am getting back the response fine.
How can I access the requestData?

Dave's solution in the comments worked:
Changed ajax request to:
request = $.ajax({
url: "/api/comments",
method: "GET",
dataType: "json",
data: {data : requestData}
});

This is how push item in an array using jQuery:
function ApproveUnapproveVisitors(approveUnapprove){
var arrUserIds = [];
$(".visitors-table>tbody>tr").each(function(index, tr){
arrUserIds.push($(this).find('a').attr('data-user-id'));
});
$.ajax({
type:'POST',
url:'/dashboard/whitelistedusers/' + approveUnapprove,
headers: {'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')},
data: {data : arrUserIds},
success:function(data){
alert(data.success);
},
error: function(e){
//alert(e.error);
}
});
}
And this is how I access them in my controller
//Approve all visitors
function ApproveAllWhitelistedUsers(Request $request){
$arrToSend = request('data');
foreach ($arrToSend as $visitor) {
$vsitor = User::findOrFail($visitor);
$vsitor->update(['is_approved'=> '1']);
}
return response()->json(['success'=>'Accounts approved successfully!']);
}

JQuery $.ajax() post - data in a java servlet

I want to send data to a java servlet for processing. The data will have a variable length and be in key/value pairs:
{ A1984 : 1, A9873 : 5, A1674 : 2, A8724 : 1, A3574 : 3, A1165 : 5 }
The data doesn't need to be formated this way, it is just how I have it now.
var saveData = $.ajax({
type: "POST",
url: "someaction.do?action=saveData",
data: myDataVar.toString(),
dataType: "text",
success: function(resultData){
alert("Save Complete");
}
});
saveData.error(function() { alert("Something went wrong"); });
The $.ajax() function works fine as I do get an alert for "Save Complete". My dilemna is on the servlet. How do I retrieve the data? I tried to use a HashMap like this...
HashMap hm = new HashMap();
hm.putAll(request.getParameterMap());
...but hm turns out to be null which I am guessing means the .getParameterMap() isn't finding the key/value pairs. Where am I going wrong or what am I missing?

You don't want a string, you really want a JS map of key value pairs. E.g., change:
data: myDataVar.toString(),
with:
var myKeyVals = { A1984 : 1, A9873 : 5, A1674 : 2, A8724 : 1, A3574 : 3, A1165 : 5 }
var saveData = $.ajax({
type: 'POST',
url: "someaction.do?action=saveData",
data: myKeyVals,
dataType: "text",
success: function(resultData) { alert("Save Complete") }
});
saveData.error(function() { alert("Something went wrong"); });
jQuery understands key value pairs like that, it does NOT understand a big string. It passes it simply as a string.
UPDATE: Code fixed.

Simple method to sending data using java script and ajex call.
First right your form like this
<form id="frm_details" method="post" name="frm_details">
<input id="email" name="email" placeholder="Your Email id" type="text" />
<button class="subscribe-box__btn" type="submit">Need Assistance</button>
</form>
javascript logic target on form id #frm_details after sumbit
$(function(){
$("#frm_details").on("submit", function(event) {
event.preventDefault();
var formData = {
'email': $('input[name=email]').val() //for get email
};
console.log(formData);
$.ajax({
url: "/tsmisc/api/subscribe-newsletter",
type: "post",
data: formData,
success: function(d) {
alert(d);
}
});
});
})
General
Request URL:https://test.abc
Request Method:POST
Status Code:200
Remote Address:13.76.33.57:443
From Data
email:abc#invalid.ts

you can use ajax post as :
$.ajax({
url: "url",
type: "POST",
dataType: "json",
contentType: "application/json; charset=utf-8",
data: JSON.stringify({ name: 'value1', email: 'value2' }),
success: function (result) {
// when call is sucessfull
},
error: function (err) {
// check the err for error details
}
}); // ajax call closing

For the time being I am going a different route than I previous stated. I changed the way I am formatting the data to:
&A2168=1&A1837=5&A8472=1&A1987=2
On the server side I am using getParameterNames() to place all the keys into an Enumerator and then iterating over the Enumerator and placing the keys and values into a HashMap. It looks something like this:
Enumeration keys = request.getParameterNames();
HashMap map = new HashMap();
String key = null;
while(keys.hasMoreElements()){
key = keys.nextElement().toString();
map.put(key, request.getParameter(key));
}

To get the value from the servlet from POST command, you can follow the approach as explained on this post by using request.getParameter(key) format which will return the value you want.