DataTable and ajax json

HTML

<script src="https://cdn.datatables.net/1.10.20/js/jquery.dataTables.min.js"></script>
<link rel="stylesheet" href="https://cdn.datatables.net/1.10.20/css/jquery.dataTables.min.css">
<table id="table">
  <thead>
    <tr>
      <th>Id</th>
      <th>Col1</th>
      <th>Col2</th>
      <th>Col3</th>
    </tr>
  </thead>
</table>

JavaScript

var json = [{
    "name": "Tiger Nixon",
    "hr": {
        "position": "System Architect",
        "salary": "$3,120",
        "start_date": "2011/04/25"
    },
    "contact": {
    	"city" :"Edinburgh",
      "Street":"5421"
    }
}]

$("#table").DataTable({
  ajax: {
    url: "/echo/json/",
    method: 'POST',
    data: {
      json: JSON.stringify(json)
    },
		dataSrc: ''
  },
  columns: [{
      "data": "name"
    },
    {
      "data": "hr.position"
    },
    {
      "data": "hr.salary"
    },
    {
      "data": "contact.city"
    }
  ],
  });