ngrepeat does not iterate $ attribute - angularjs

Question

I tried filtering with an object and to print out the filters via ng-repeat = (key, value) in object.
As I tried various filters, I saw that ng-repeat does not seem to work with the object's $ attribute, which is pretty useful if you are filtering.
Is there a possibility to show all attributes of the filtering objects automatically even if you use $
This link shows it doesn't seem to work with objects starting with $
$scope.testObj = {};
$scope.testObj.test = 'test';
$scope.testObj.$ = '$';
$scope.testObj.$test = '$test';
<div ng-repeat = "(key, value) in testObj">
<p>{{key}}: {{value}}</p>
</div>

Answer 1

AngularJS doesn't support it yet. There is an open issue on Github.
However you can make it work with a little code:
app.controller('MainCtrl', function($scope) {
var getProperties = function(input){
var result = [];
for(var propertyName in input) {
result.push({key : propertyName, value : input[propertyName]});
}
return result;
};
$scope.testObj = {};
$scope.testObj.test = 'test';
$scope.testObj.$ = '$';
$scope.testObj.$whatever = '$whatever';
$scope.testObjProperties = getProperties($scope.testObj);
});
Then display it in your view:
<div ng-repeat="property in testObjProperties">
<p>{{property.key}} : {{property.value}}</p>
</div>
Here's a working plunk : http://plnkr.co/edit/LFrfLcpoOg0ScEY89p25?p=preview

Answer 2

Looks like ng-repeat filters out object properties that begin with $.
This is from the source:
for (var itemKey in collection) {
if (collection.hasOwnProperty(itemKey) && itemKey.charAt(0) != '$') {
collectionKeys.push(itemKey);
}
}
This is most likely due to the fact that Angular uses $ to indicate code that is internal to the Angular library.
It seems this will only occur if you are using ng-repeat over an object.

Answer 3

I see them being disallowed specifically in the code:
https://github.com/angular/angular.js/blob/master/src/ng/directive/ngRepeat.js#L341
There are no comments around, and I agree this looks more than a bug than a feature, to me. Isn't that what marking properties as non-enumerable and Object.keys is for?
Browser compatibility hell, may be the reason, as always.