JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.1.1/css/bootstrap.min.css">
<div class="container">
    <div class="row">
        <div class="col-xs-6"><i></i></div>
        <div class="col-xs-6"><i></i></div>
        <div class="col-xs-12">
        <div class="col-xs-6">
            <div class="col-xs-12"><i></i></div>
            <div class="col-xs-12"><i></i></div>
        </div>
        <div class="col-xs-6"><i></i></div>
    </div>
    </div>
</div>

CSS

div {
    background:rgba(0,0,0,0.2);
    border: 1px solid #000;
}
i {
    border: 1px solid blue;
    display:block;
    height: 200px;
    
}

JavaScript

(function($) {
    var $els = $('[class^="col-"');
    //console.log($els);
    var cols = {};
    $els.each(function(i, col) {
        var classes = $(col).attr('class').split(' ');
        
        classes.forEach(function(str) {
            var match = str.match(/col-(\w+)-(\d+)/);
            if ( match ) {
                //console.log($els.eq(i));
                cols[match[1]] = cols[match[1]] || {};
                var current = cols[match[1]];
                
                if ( match[2] == 12 ) {
                    current.ids = [];
                    current.sum = 0;
                    
                    $els.eq(i).css({ padding: 0 });
                    return
                }
                
                current.ids = current.ids || [];
                current.sum = current.sum || 0;
                current.sum += ( +match[2] );
                current.ids.push(i);
                if (current.sum == 12) {
                    //console.log(current);
                    current.ids.forEach(function(id) {
                        $els.eq(id).css({ 'padding': 0, 'padding-right': '15px' });
                        if (id == i) $els.eq(id).css({ 'padding': 0, 'padding-left': '15px' });
                    });
                    current.ids = [];
                    current.sum = 0;
                }
            }
        });
    });
})(jQuery);