JSFiddle - React, Tailwind, and code Playground

HTML

<div class="btn-group-vertical" data-toggle="buttons-checkbox">
  <button type="button" class="btn customwidth"><i class="icon-rss"></i> news</button>
  <button type="button" class="btn customwidth active"><i class="icon-bullhorn"></i> opinion</button>
  <button type="button" class="btn customwidth active"><i class="icon-lightbulb"></i> research</button>
  <button type="button" class="btn customwidth"><i class="icon-signal"></i> stats</button>
  <button type="button" class="btn customwidth active"><i class="icon-info-sign"></i> how to...</button>
  <button type="button" class="btn customwidth"><i class="icon-desktop"></i> platform/app</button>  
  <button type="button" class="btn customwidth"><i class="icon-cloud"></i> tool</button>
  <button type="button" class="btn customwidth"><i class="icon-minus-sign"></i> uncategorised</button>    
</div>
<div id="result"></div>

JavaScript

$(function(){
$
    //$('#result').text('result: ');
    var array = [];
    ("button").click(function () {
    $('.btn-group-vertical').find('button.active > i').map(function(){
        array.push(this.className);
    });
    });
    $('#result').text(JSON.stringify(array));

});