Bootstrap3 collapse consecutive transition fix and tidy up

src/collapse/collapse.js

@@ -8,39 +8,43 @@ angular.module('ui.bootstrap.collapse', ['ui.bootstrap.transition'])
         var initialAnimSkip = true;
         var currentTransition;
 
-        function resetCurrentTransition() {
-          currentTransition = undefined;
-        }
-
         function doTransition(change) {
+          var newTransition = $transition(element, change);
           if (currentTransition) {
             currentTransition.cancel();
           }
-          (currentTransition = $transition(element, change)).then(resetCurrentTransition, resetCurrentTransition);
-          return currentTransition;
+          currentTransition = newTransition;
+          newTransition.then(newTransitionDone, newTransitionDone);
+          return newTransition;
+
+          function newTransitionDone() {
+            // Make sure it's this transition, otherwise, leave it alone.
+            if (currentTransition === newTransition) {
+              currentTransition = undefined;
+            }
+          }
         }
 
         function expand() {
           if (initialAnimSkip) {
             initialAnimSkip = false;
-            element.removeClass('collapsing');
-            element.addClass('collapse in');
-            element.css({height: 'auto'});
+            expandDone();
           } else {
             element.removeClass('collapse').addClass('collapsing');
-            doTransition({ height: element[0].scrollHeight + 'px' }).then(function () {
-              element.removeClass('collapsing');
-              element.addClass('collapse in');
-              element.css({height: 'auto'});
-            });
+            doTransition({ height: element[0].scrollHeight + 'px' }).then(expandDone);
           }
         }
 
+        function expandDone() {
+          element.removeClass('collapsing');
+          element.addClass('collapse in');
+          element.css({height: 'auto'});
+        }
+
         function collapse() {
           if (initialAnimSkip) {
             initialAnimSkip = false;
-            element.removeClass('collapsing');
-            element.addClass('collapse');
+            collapseDone();
             element.css({height: 0});
           } else {
             // CSS transitions don't work with height: auto, so we have to manually change the height to a specific value
@@ -50,13 +54,15 @@ angular.module('ui.bootstrap.collapse', ['ui.bootstrap.transition'])
 
             element.removeClass('collapse in').addClass('collapsing');
 
-            doTransition({ height: 0 }).then(function () {
-              element.removeClass('collapsing');
-              element.addClass('collapse');
-            });
+            doTransition({ height: 0 }).then(collapseDone);
           }
         }
 
+        function collapseDone() {
+          element.removeClass('collapsing');
+          element.addClass('collapse');
+        }
+
         scope.$watch(attrs.collapse, function (shouldCollapse) {
           if (shouldCollapse) {
             collapse();

src/collapse/test/collapse.spec.js

@@ -55,6 +55,23 @@ describe('collapse directive', function () {
     expect(element.height()).not.toBe(0);
   });
 
+  it('should expand if isCollapsed = true with animation on subsequent uses', function() {
+    scope.isCollapsed = false;
+    scope.$digest();
+    scope.isCollapsed = true;
+    scope.$digest();
+    scope.isCollapsed = false;
+    scope.$digest();
+    scope.isCollapsed = true;
+    scope.$digest();
+    $timeout.flush();
+    expect(element.height()).toBe(0);
+    if ($transition.transitionEndEventName) {
+      element.triggerHandler($transition.transitionEndEventName);
+      expect(element.height()).toBe(0);
+    }
+  });
+
   describe('dynamic content', function() {
     beforeEach(function() {
       element = angular.element('<div collapse="isCollapsed"><p>Initial content</p><div ng-show="exp">Additional content</div></div>');