Recalculate colum on ordering

by Colin Marks

HTML

<link rel="stylesheet" href="https://cdn.datatables.net/1.10.19/css/jquery.dataTables.min.css">
<script src="https://cdn.datatables.net/1.10.19/js/jquery.dataTables.min.js"></script>
<input type="text" id="initialInput" value="20"/>
<table id="mytable">
<thead><tr></tr><th>column1</th>
<th>column2</th>
<th>column3</th></tr>
</thead>
<tbody>
<tr>
  <td>val1</td>
  <td>5</td>
  <td></td>
</tr>
<tr>
  <td>val2</td>
  <td>2</td>
  <td></td>
</tr>
<tr>
  <td>val3</td>
  <td>3</td>
  <td></td>
</tr>
</tbody>
</table>

JavaScript

// JavaScript source code
// find elements
var initVal = $("#initialInput").val() * 1;
var myTable = $('#mytable').DataTable({
    select: {
        info: false
    },
    ordering: true,
    columns: [
            {
                "data": "column1",
                "name": "column1",
                "className":"text-center",
                "orderable": true,
            },

            {
                "data": "column2",
                "name": "column2",
                "className":"text-center",
                "orderable": false,
            },
          {
              "data": "column3",
              "type": "formatted-num",
              "className":"text-center",
              "orderable": true
              }
         ],
          "drawCallback": function( settings) {
         			var tableJq = this.api();
              var colTindex = 2;
              if (tableJq.rows().count() > 0) {
        					if (initVal == 0 || typeof initVal == 'undefined') {
            				return;
        					}
        				  else {
									var tableData = tableJq.rows({order:'current'}).data().toArray();
            			for (var j = 0; j < tableJq.rows().count() ; j++) {
								   		var smColSource = 0;
                   		for (var i = 0; i < j+1 ; i++) {
                   		smColSource +=  tableData[i].column2 * 1;
                			}
       								
                      tableJq.cell(':eq('+j+')', colTindex).data(initVal * 1 - smColSource * 1);
                      console.log(tableJq.cell(j, colTindex).data());
                  }
                 }
    				}
				}
   });