fix(dropdown): unbind toggle element event on scope destroy

Also, change the way disabled dropdownToggle is read from `attrs` instead of element property.

Closes #1867
Closes #1870

Author: bekos

src/dropdown/docs/demo.html

@@ -14,7 +14,7 @@
 
     <!-- Single button -->
     <div class="btn-group" dropdown is-open="status.isopen">
-      <button type="button" class="btn btn-primary dropdown-toggle">
+      <button type="button" class="btn btn-primary dropdown-toggle" ng-disabled="disabled">
         Button dropdown <span class="caret"></span>
       </button>
       <ul class="dropdown-menu" role="menu">
@@ -45,6 +45,7 @@
     <hr />
     <p>
         <button type="button" class="btn btn-default btn-sm" ng-click="toggleDropdown($event)">Toggle button dropdown</button>
+        <button type="button" class="btn btn-warning btn-sm" ng-click="disabled = !disabled">Enable/Disable</button>
     </p>
 
 </div>

src/dropdown/dropdown.js

@@ -112,22 +112,28 @@ angular.module('ui.bootstrap.dropdown', [])
         return;
       }
 
-      element.bind('click', function(event) {
+      var toggleDropdown = function(event) {
         event.preventDefault();
         event.stopPropagation();
 
-        if ( !element.hasClass('disabled') && !element.prop('disabled') ) {
+        if ( !element.hasClass('disabled') && !attrs.disabled ) {
           scope.$apply(function() {
             dropdownCtrl.toggle();
           });
         }
-      });
+      };
+
+      element.bind('click', toggleDropdown);
 
       // WAI-ARIA
       element.attr({ 'aria-haspopup': true, 'aria-expanded': false });
       scope.$watch(dropdownCtrl.isOpen, function( isOpen ) {
         element.attr('aria-expanded', !!isOpen);
       });
+
+      scope.$on('$destroy', function() {
+        element.unbind('click', toggleDropdown);
+      });
     }
   };
 });

src/dropdown/test/dropdown.spec.js

@@ -91,6 +91,35 @@ describe('dropdownToggle', function() {
       expect(elm.hasClass('open')).toBe(false);
     });
 
+    it('should not toggle if the element has `ng-disabled` as true', function() {
+      $rootScope.isdisabled = true;
+      var elm = $compile('<li class="dropdown"><div ng-disabled="isdisabled" dropdown-toggle></div><ul><li>Hello</li></ul></li>')($rootScope);
+      $rootScope.$digest();
+      elm.find('div').click();
+      expect(elm.hasClass('open')).toBe(false);
+
+      $rootScope.isdisabled = false;
+      $rootScope.$digest();
+      elm.find('div').click();
+      expect(elm.hasClass('open')).toBe(true);
+    });
+
+    it('should unbind events on scope destroy', function() {
+      var $scope = $rootScope.$new();
+      var elm = $compile('<li class="dropdown"><button ng-disabled="isdisabled" dropdown-toggle></button><ul><li>Hello</li></ul></li>')($scope);
+      $scope.$digest();
+
+      var buttonEl = elm.find('button');
+      buttonEl.click();
+      expect(elm.hasClass('open')).toBe(true);
+      buttonEl.click();
+      expect(elm.hasClass('open')).toBe(false);
+
+      $scope.$destroy();
+      buttonEl.click();
+      expect(elm.hasClass('open')).toBe(false);
+    });
+
     // issue 270
     it('executes other document click events normally', function() {
       var checkboxEl = $compile('<input type="checkbox" ng-click="clicked = true" />')($rootScope);