Push a variable into an array and update the array each time we click?

I am saving a variable into an array with a click on an item, but this should change each time I click on a different item. Currently this is alerting the same value and not the new one.

<div class="item">
     <span id="0" class="video" data-vimeoid="http://vimeo.com/XXX"></span>
</div>
<div class="item">
  <span id="1" class="video" data-vimeoid="http://vimeo.com/SSS"></span>
</div>
<div class="item">
  <span id="2" class="video" data-vimeoid="http://vimeo.com/ZZZ"></span>
</div>

Then in jQuery

var previous = [];
$(document).on( 'click', '.item:not(.is-expanded)', function() {
    var url = videoSpan.data("vimeoid");
    previous.push(url);
    alert(previous[0]);
});