How to use track by using angularJs directive ng-repeat?
<p>I have a data from backend <code>userList</code>but its not displaying in table any idea what is implemented wrong in below code using <code>ng-repeat</code>.  </p>

<p>main.html</p>

<pre><code> &lt;tr ng-repeat="user in userList track by $index"&gt;
    &lt;td st-ratio="20"&gt;{{user.attuid}}&lt;/td&gt;
    &lt;td st-ratio="30"&gt;{{user.firstName}} {{user.lastName}}&lt;/td&gt;
    &lt;td st-ratio="15" ng-bind-html="user.type"&gt;&lt;/td&gt;
    &lt;td st-ratio="15"&gt;{{user.email}}&lt;/td&gt;
    &lt;td st-ratio="20" class="text-right"&gt;
      &lt;button tooltip-placement="top" tooltip-popup-delay="300" uib-tooltip="Edit" type="button" ng-click="editUser($index, user)" class="btn btn-sm btn-secondary"&gt;
        &lt;i class="glyphicon glyphicon-pencil"&gt;&lt;/i&gt;
      &lt;/button&gt;
      &lt;button tooltip-placement="top" tooltip-popup-delay="300" uib-tooltip="Delete" ng-disabled="currentUser.id === user._id" type="button" ng-click="deleteUser($index, user)" class="btn btn-sm btn-danger"&gt;
        &lt;i class="glyphicon glyphicon-remove-circle"&gt;&lt;/i&gt;
      &lt;/button&gt;
    &lt;/td&gt;
  &lt;/tr&gt;
</code></pre>

<p>controller.js</p>

<pre><code>$scope.userList = data
</code></pre>

<p>data printing in console</p>

<pre><code>Array[1]
0
:
Object
__v
:
0
_id
:
"585419276bef8729e8e4d08e"
attuid
:
"sh89u"
email
:
"sh9829u@gmail.com"
firstName
:
"Syed"
lastName
:
"Hussain"
</code></pre>