title: how to make simple directed graph using d3
body: <p>I am trying to create a simple force layout directed-edge graph base on this D3.js example "<a href="http://bl.ocks.org/1153292" rel="nofollow noreferrer">http://bl.ocks.org/1153292</a>".</p>
  
  <p>There is line where it says <code>.data(["suit", "licensing", "resolved"])</code> but I have no clue what that means. I have to admit I don't fully understand the details of it.</p>
  
  <p>I have looked at a few so questions but none was helpful.</p>
  
  <p>I would really appreciate it if </p>
  
  <ol>
  <li><p>sb can tell what ".data(["suit", "licensing", "resolved"])" means.</p></li>
  <li><p>How are arrows added to the end of the edges.</p></li>
  </ol>