Crossfilter arrays as keys

Trying to find a way how to expand array of keys into separate records, one per element of array

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/crossfilter/1.1.3/crossfilter.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/dc/1.3.0/dc.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.2.2/d3.v3.min.js"></script>
<div id="chart"></div>

JavaScript

var data = [
    {"key":"KEY-1","tags":["tag1", "tag2"]},
    {"key":"KEY-2","tags":["tag2"]},
    {"key":"KEY-3","tags":["tag3", "tag1"]}];

var cf = crossfilter(data);

var tags = cf.dimension(function(d){ return d.tags;});
var tagsGroup = tags.group();


dc.rowChart("#chart")
    .renderLabel(true)
    .dimension(tags)
    .group(tagsGroup)
    .xAxis().ticks(3);

dc.renderAll();