Datatables TypeError: c is undefined

Question

I try to use jQuery DataTables but I get the error

TypeError: c is undefined

I don't know what is wrong with my code as I can see the JSON correctly retrieve and is in the correct format too but I don't know what is wrong with it that I get the above error.

My JSON :

{"Data":[{"LOGIN":10184},{"LOGIN":10214},{"LOGIN":10180},{"LOGIN":10187},{"LOGIN":10179},{"LOGIN":10280},{"LOGIN":201},{"LOGIN":10238},{"LOGIN":10296},{"LOGIN":10312}]}

and my DataTables code:

$(document).ready(function() {
    $('#tablename').dataTable( {
        "processing": true,
        "serverSide": true,
        "ajax": {
            "type": "POST",
        "url": "https://test.com/api/db/select",
        "data": function ( json ) {  return JSON.stringify( { "Sql": 12 } );},
        "contentType": "application/json; charset=utf-8",
        "dataType": "json",
        "processData": true,
            beforeSend : function(xhr){
                        var access_token = sessionStorage.getItem('access_token');
                        xhr.setRequestHeader('Authorization', 'Bearer ' + access_token);
            }
        },
        "dataSrc": "Data",
        "columns": [
            { "data": "LOGIN" }
        ]
    } );
} );

Answer 1

Sometime, This type issue arrives by fixing mismatched / unequal columns with HTML and datatables columns.

"columns": [
        null,
        null,
        null,
        {"orderable": false, "width":"2%"},
    ],

Above javascript defined 4 columns and HTML having 5 columns

<tr>
   <td>A</td>
   <td>B</td>
   <td>C</td>
   <td>D</td>
   <td>E</td>
</tr>

Hence you will have to fix / equal both side HTMl and Datatable configuration.

"columns": [
        null,
        null,
        null,
        null, //Added New
        {"orderable": false, "width":"2%"},
    ],

Answer 2

in my case, i had to remove colspan attribute from a th inside thead and get rid of the error ;(

Answer 3

In my case, I got the same error because I used the ajax.dataSrc( data ) function to manipulate the data. But after that i forgot to return the data.

"dataSrc": function ( json ) {
  for ( var i=0, ien=json.data.length ; i<ien ; i++ ) {
      //somethings...
  }
  return json.data;// I forgot this line, then i got the error "TypeError: c is undefined"
}

After a few minutes, I checked the documentation of the ajax.dataSrc function and I noticed that I did not have the return:

Returns: array. Array of data that DataTables is to use to draw the table

I hope you do not have the same distraction...

Answer 4

dataSrc is a special dataTables ajax option, that should be included inside the ajax object :

"ajax": {
    "dataSrc": "Data", //<--- place dataSrc here instead
    "type": "POST",
    ...
}

You have placed it outside ajax, and by that dataTables have no idea what source to use (besides blindly trying the ajax response) or where LOGIN belongs.

Answer 5

Check whether you have added

<thead></thead>

<tbody></tbody>

I've resolved this problem by adding those.

So basically the structure must be like:

<table>
 <thead>
  <tr>
   <th></th>
   <th></th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td></td>
   <td></td>
  </tr>
 </tbody>
</table>