Progress indication in angularjs, while promises :)

controller.coffee

MyController = ($scope, $resource)->
  $scope.items = $resource.query()

directive.coffee

window.ngApp.directive 'progressLoader', ($filter) ->
  restrict: "A"
  scope: null
  link: (scope, element, attributes) ->
    watchCallback = (newValue, oldValue) ->
      if newValue?.$resolved == false
        element.show()
      else
        element.hide()

    scope.$watch attributes.promise, watchCallback, true

usage.html

<div class="loader" progress-loader promise="items"> Loading...do more with css :)</div>
<ul>
  <li ng-repeat="item in items"> {{item.label}}</li>
</ul>

For this specific case (waiting on a list that's being used in a repeat), I think it would be cleaner to just use:

<div class="loader" ng-hide="items.length > 0"> Loading... </div>

thx for simplification,
but i'm looking for generic solution
i don't want to guess about promise result.

This directive can be extended with animation and progress percentage, based on request statistics.

I agree with @smmccrohan. Using promise="items" attribute is a distortion of the concept of promises.
Using ng-hide allows any process to update/modify that data model... this is a better approach AND it eliminates the need for the extra directive.