fix($animate): ensure all animated elements are taken care of during the closing timeout

Closes angular#6395

Author: matsko

src/ngAnimate/animate.js

@@ -1081,17 +1081,22 @@ angular.module('ngAnimate', ['ng'])
       var closingTimestamp = 0;
       var animationElementQueue = [];
       function animationCloseHandler(element, totalTime) {
+        var node = extractElementNode(element);
+        element = angular.element(node);
+
+        //this item will be garbage collected by the closing
+        //animation timeout
+        animationElementQueue.push(element);
+
+        //but it may not need to cancel out the existing timeout
+        //if the timestamp is less than the previous one
         var futureTimestamp = Date.now() + (totalTime * 1000);
         if(futureTimestamp <= closingTimestamp) {
           return;
         }
 
         $timeout.cancel(closingTimer);
 
-        var node = extractElementNode(element);
-        element = angular.element(node);
-        animationElementQueue.push(element);
-
         closingTimestamp = futureTimestamp;
         closingTimer = $timeout(function() {
           closeAllAnimations(animationElementQueue);
@@ -1345,7 +1350,7 @@ angular.module('ngAnimate', ['ng'])
 
         var staggerTime       = itemIndex * (Math.max(stagger.animationDelay, stagger.transitionDelay) || 0);
         var animationTime     = (maxDelay + maxDuration) * CLOSING_TIME_BUFFER;
-        var totalTime         = (staggerTime + animationTime) * ONE_SECOND;
+        var totalTime         = staggerTime + animationTime * ONE_SECOND;
 
         elementData.running++;
         animationCloseHandler(element, totalTime);

test/ngAnimate/animateSpec.js

@@ -1189,6 +1189,54 @@ describe("ngAnimate", function() {
             expect(element.hasClass('some-class-add-active')).toBe(false);
           }));
 
+          it("should intelligently cancel former timeouts and close off a series of elements a final timeout", function() {
+            var cancellations = 0;
+            module(function($provide) {
+              //temporarily override this factory so that the cancellations
+              //are only counted for the the animations
+              //
+              // TODO(matsko): remove this line once rAF callbacks are merged
+              $provide.value('$$asyncQueueBuffer', angular.noop);
+              $provide.decorator('$timeout', function($delegate) {
+                var _cancel = $delegate.cancel;
+                $delegate.cancel = function() {
+                  cancellations++;
+                  return _cancel.apply($delegate, arguments);
+                };
+                return $delegate;
+              });
+            })
+            inject(function($animate, $rootScope, $compile, $sniffer, $timeout) {
+              if (!$sniffer.transitions) return;
+
+              ss.addRule('.animate-me', '-webkit-transition:1s linear all;' +
+                                                      'transition:1s linear all;');
+
+              element = $compile(html('<div><div class="animate-me" ng-repeat="item in items"></div></div>'))($rootScope);
+
+              $rootScope.items = [1,2,3,4,5,6,7,8,9,10];
+              var totalOperations = $rootScope.items.length;
+
+              $rootScope.$digest();
+
+              $rootScope.items = [0];
+              $animate.triggerReflow();
+              $timeout.flush(1500);
+
+              expect(cancellations).toBeLessThan(totalOperations);
+              expect(element.children().length).toBe(10);
+              cancellations = 0;
+
+              $rootScope.items = [1];
+              $rootScope.$digest();
+
+              $animate.triggerReflow();
+              $timeout.flush(1500);
+              expect(element.children().length).toBe(1);
+              expect(cancellations).toBeLessThan(totalOperations);
+            });
+          });
+
           it("apply a closing timeout with respect to a staggering animation",
             inject(function($animate, $rootScope, $compile, $sniffer, $timeout) {