How to compare AngularJS value to ruby on rails variable value

I am using Firebase in a pretty simple chat application. One of the features i'm working on now is the ability to update messages in the chat room, but only if you were the original author. For the editing i have an icon that, when clicked, will do some javascript to hide the message div and display a previously hidden div that has the update form in it. But i only want this to be available if you were the author of the message. Here's what the code looks like:

<li class="message phm pvm pull-left" ng-repeat="(msgId,msg) in room.messages">
  <div class="message-current" data-message-id="{{msgId}}">
    <span class="message-author pull-left">{{msg.author}}</span>
    <span class="message-body pull-left pls">{{msg.body}}</span>
    <span class="message-timestamp pull-right prs">
      {{msg.timestamp | date:'MMM d, yyyy h:mm a'}}
      <a class="message-update-link" href="#" ng-click="showMessageUpdate(msgId)"><span class="glyphicon glyphicon-pencil"></span></a>
    </span>
  </div>
  <div class="message-update hidden" data-message-id="{{msgId}}">
    <form class="form-inline" ng-submit="updateMessage(roomId, msgId, '<%= current_user.full_name %>')">
      <textarea class="form-control update-message" ng-model="msg.body" ng-trim="false">{{msg.body}}</textarea>
      <input class="button button-large button-primary" type="submit" value="Update">
    </form>
  </div>
</li>

Right now, i can only get it to have updatable message for ALL message or no messages. Basically, the part i am stuck on is the check of whether or not the angularjs value of {{msg.author}} is equal to the rails value of <%= current_user.id %>. Any thoughts on how this can be achieved? Thanks for any help!

SOLVED:
Thanks to Jiten for the step in the right direction. I'm new to learning AngularJS and it's pretty complex. Sometimes you just need to know where to start.

I ended up using a combination of the ngIf directive and the angular.equals function. In my rails view i used ng-if="isAuthor(msg.author, '<%= current_user.full_name %>')" on anything i wanted available to authors of that message only. This will evaluate the response of isAuthor() and only render to the dom if it evaluates to true. The code above now looks like this:

<li class="message phm pvm pull-left" ng-repeat="(msgId,msg) in room.messages">
  <div class="message-current" data-message-id="{{msgId}}">
    <span class="message-author pull-left">{{msg.author}}</span>
    <span class="message-body pull-left pls">{{msg.body}}</span>
    <span class="message-timestamp pull-right prs">
      {{msg.timestamp | date:'MMM d, yyyy h:mm a'}}
      <a ng-if="isAuthor(msg.author, '<%= current_user.full_name %>')" class="message-update-link" href="#" ng-click="showMessageUpdate(msgId)"><span class="glyphicon glyphicon-pencil"></span></a>
    </span>
  </div>
  <div ng-if="isAuthor(msg.author, '<%= current_user.full_name %>')" class="message-update hidden" data-message-id="{{msgId}}">
    <form class="form-inline" ng-submit="updateMessage(roomId, msgId, '<%= current_user.full_name %>')">
      <textarea class="form-control update-message" ng-model="msg.body" ng-trim="false">{{msg.body}}</textarea>
      <input class="button button-large button-primary" type="submit" value="Update">
    </form>
  </div>
</li>

Here is what isAuthor() looks like in my AngularJS controller:

$scope.isAuthor = function(msgAuthor, currentUser) {
   return angular.equals(msgAuthor, currentUser);
}

Pretty simple really!