Ionic - load image from ipad filesystem

I am building an Ionic app for iPad. One of the requirements is to open a PNG Image in the app.

I am using $cordovaFile.readAsDataURL to read the image from iPad filesystem and show in the app, however, it goes into some kind of infinite loop.

In my html

<div style="text-align:center;">
          <img ng-src="{{getDoc(item.fileName)}}" width="100%" height="auto">
        </div>

In the controller

$scope.getDoc = function (fileName) {
return $cordovaFile.readAsDataURL(cordova.file.dataDirectory, $rootScope.username + "/thb/" + fileName + ".png")
                    .then(function (success) {
                        console.log("success", JSON.stringify(success));
                        return success;

                    }, function (error) {
                        console.log("error....", JSON.stringify(error));
                    });
        };

The output in safari developer tools shows that it has gone into some kind of infinite loop, as the output never ends It looks like (small snippet)

success – "\"data:image/png;base64,/9j/4AAQSkZJRgABAgAAZABkAAD/7AARRHVja3kAAQAEAAAAZAAA/+4AJkFkb2JlAGTAAAAAAQMAFQQDBgoNAAFTFQAB3i0AAwHQAAUITP/bAIQAAQEBA…"

It keeps on printing this again and again. How can I read a png file from iPad file system and show it in the Ionic app.

I have also tried readAsDataURL but with the same result.