title: adjacency list using json object
body: <p>I want to create a adjacency list using json object. I would like to implement json object for adjacency list in the following format.</p>
  
  <pre><code>var JSONobj= {node1:[{x1,y1},{x3,y3},{x4,y4}], node2:[{x2,y2},{x3,y3}], node3:[]}
  </code></pre>
  
  <p>My doubt is, whether I can add values to coordinate list dynamically such as <code>JSONobj.node3[0]={x4,y4}</code>? 
  or is there any better way to add values to JSONobj from outside the object declaration?</p>