jQuery DataTables: How to expand/collapse all child rows - Regular table

Example for article at https://www.gyrocode.com/articles/jquery-datatables-how-to-expand-collapse-all-child-rows/

HTML

<link rel="stylesheet" href="https://cdn.datatables.net/v/dt/dt-1.10.16/datatables.min.css">
<script src="https://cdn.datatables.net/v/dt/dt-1.10.16/datatables.min.js"></script>
<button id="btn-show-all-children" type="button">Expand All</button>
<button id="btn-hide-all-children" type="button">Collapse All</button>
<hr>
<table id="example" class="display" cellspacing="0" width="100%">
    <thead>
        <tr>
				    <th></th>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Salary</th>
        </tr>
    </thead>
    <tfoot>
        <tr>
				    <th></th>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Salary</th>
        </tr>
    </tfoot>
</table>

CSS

td.details-control {
    background: url('https://cdn.rawgit.com/DataTables/DataTables/6c7ada53ebc228ea9bc28b1b216e793b1825d188/examples/resources/details_open.png') no-repeat center center;
    cursor: pointer;
}
tr.shown td.details-control {
    background: url('https://cdn.rawgit.com/DataTables/DataTables/6c7ada53ebc228ea9bc28b1b216e793b1825d188/examples/resources/details_close.png') no-repeat center center;
}

JavaScript

/* Formatting function for row details - modify as you need */
function format ( d ) {
	var childId = d.extn;
  var div = $('<div><table id=\'child-table' + childId + '\' class=\'table-striped table-bordered\' width="100%"></table></div>');
  
  
      var childTable = $('table', div).DataTable({
        colReorder: true,
        searching: false,
        info: false,
        paging: false,
        data: d.children,
        columns: [{
            title: "Name",
            render: function(data, type, row, meta) {
              return row.name;
            }
          },
          {
            title: "Class",
            render: function(data, type, row, meta) {
              return row.class;
            }
          },
        ]
      });

	return div;
}


$(document).ready(function() {
    var table = $('#example').DataTable({
        'ajax': 'https://api.myjson.com/bins/17z2am',
        'columns': [
            {
                'className':      'details-control',
                'orderable':      false,
                'data':           null,
                'defaultContent': ''
            },
            { 'data': 'name' },
            { 'data': 'position' },
            { 'data': 'office' },
            { 'data': 'salary' }
        ],
        'order': [[1, 'asc']]
    } );

    // Add event listener for opening and closing details
    $('#example tbody').on('click', 'td.details-control', function(){
        var tr = $(this).closest('tr');
        var row = table.row( tr );

        if(row.child.isShown()){
            // This row is already open - close it
            row.child.hide();
            tr.removeClass('shown');
        } else {
            // Open this row
            row.child(format(row.data())).show();
            tr.addClass('shown');
        }
    });

    // Handle click on "Expand All" button
    $('#btn-show-all-children').on('click', function(){
        // Enumerate all rows
        table.rows().every(function(){
            // If row...