Angular Filter controller filter default display all objects if no category is selected
<p><strong>html</strong>   </p>

<pre><code>ng-click="selectCategory(item)" 
</code></pre>

<p><strong>controller</strong></p>

<pre><code> $scope.selectCategory = function (newCategory) {
            $scope.bottomValue = newCategory;
     selectedCategory = newCategory;
      $scope.selectedPage = 1;

  }

  $scope.categoryFilterFn = function (product) {
    return selectedCategory == null ||
        product.category == selectedCategory;
   }
</code></pre>

<p>I have the category filter controller side below that's working fine and filtering the array correctly however when no category has been selected no objects are selected which is not desired</p>

<p>Objective : I want all values in the array to be displayed when no category is selected
e.g. note when <code>$scope.bottomValue</code> is removed from below all the objects in the array are returned.</p>

<pre><code>$scope.edition_products = $filter('filter')( $scope.filteredItems, {approved:            true, category: $scope.bottomValue}); 
</code></pre>

<p>Note:  I no I can do this view side with filters but I want this  working controller side.</p>