I have api call on $on i got the Json response that is attached with the question. i was able to display fileName in the li , Now i have delete function when user click on remove icon i am calling function and trying to get rskAsesAprvAtchKy key so i can post the key to backend to delete this file. 
It is coming undefined i am not sure what i am missing any help will be appreciated..
main.html
<div class="row">
    <div class="col-md-6">
        <ul>
            <li ng - repeat="file in attachedDoc">{{file . fileName}}
                <a href="" ng - click="deleteFile()">
                    <span class="glyph_remove"></span>
                </a>
            </li>
        </ul>
    </div>
</div>
factory.js
$scope.$on('addEditAttest', function (s, attestorObj) {
    $scope.attestorObj = attestorObj;
    attestorFactory.getAttachedDocument($scope.attestorObj.riskAssessmentRoleAsgnKey)
        .then(function (response) {
            $scope.attachedDoc = response.data;
        });
});
$scope.deleteFile = function () {
    var fileKey;
    $scope.attachedDoc.rskAsesAprvAtchKy = fileKey;
    console.log("deleted", fileKey);
}
JSON.JS
[{
    "rskAsesAprvAtchKy": 1001,
    "fileName": "Doc 1",
    "rskAsesRoleAsgnKy": 1277
}]


fileKey = $scope.attachedDoc.idright?