Cursedproha

<button id="sort" type="button">Sort</button>
  <br><br>
  
  <div id="body">
    <div class="listing-item" data-event-date="2017-05-02">2017-05-02</div>
    <div class="listing-item" data-event-date="2018-01-07">2018-01-07</div>
    <div class="listing-item" data-event-date="2017-06-05">2017-06-05</div>
    <div class="listing-item" data-event-date="2018-01-03">2018-01-03</div>
    <div class="listing-item" data-event-date="2017-08-08">2017-08-08</div>
  </div>

const items = [...document.querySelectorAll('.listing-item')];

function compare(a, b) {
	const aData = new Date($(a).data('event-date'));
  const bData = new Date($(b).data('event-date'));
  if (aData < bData) {
    return -1;
  }
  if (aData > bData) {
    return 1;
  }
  return 0;
}

$('#sort').on('click', () => {
	items.sort(compare);
  $('#body').empty();
	items.forEach(item => {
  	$('#body').append(item);
  });
});