refactor(animations): defer the noop engine's event deregistration

modules/@angular/core/src/view/services.ts

@@ -162,9 +162,6 @@ function debugSetCurrentNode(view: ViewData, nodeIndex: number) {
 }
 
 function debugHandleEvent(view: ViewData, nodeIndex: number, eventName: string, event: any) {
-  if (view.state & ViewState.Destroyed) {
-    throw viewDestroyedError(DebugAction[_currentAction]);
-  }
   debugSetCurrentNode(view, nodeIndex);
   return callWithDebugContext(
       DebugAction.handleEvent, view.def.handleEvent, null, [view, nodeIndex, eventName, event]);

modules/@angular/platform-browser/animations/src/render/noop_animation_engine.ts

@@ -14,6 +14,7 @@ interface ListenerTuple {
   eventPhase: string;
   triggerName: string;
   callback: (event: any) => any;
+  doRemove?: boolean;
 }
 
 interface ChangeTuple {
@@ -82,12 +83,7 @@ export class NoopAnimationEngine extends AnimationEngine {
     const tuple = <ListenerTuple>{triggerName: eventName, eventPhase, callback};
     listeners.push(tuple);
 
-    return () => {
-      const index = listeners.indexOf(tuple);
-      if (index >= 0) {
-        listeners.splice(index, 1);
-      }
-    };
+    return () => tuple.doRemove = true;
   }
 
   flush(): void {
@@ -134,6 +130,16 @@ export class NoopAnimationEngine extends AnimationEngine {
       }
     });
 
+    // remove all the listeners after everything is complete
+    Array.from(this._listeners.keys()).forEach(element => {
+      const listenersToKeep = this._listeners.get(element).filter(l => !l.doRemove);
+      if (listenersToKeep.length) {
+        this._listeners.set(element, listenersToKeep);
+      } else {
+        this._listeners.delete(element);
+      }
+    });
+
     onStartCallbacks.forEach(fn => fn());
     onDoneCallbacks.forEach(fn => fn());
     this._flaggedRemovals.clear();

modules/@angular/platform-browser/animations/test/noop_animation_engine_spec.ts

@@ -121,33 +121,53 @@ export function main() {
       expect(captures).toEqual([]);
     });
 
-    it('should deregister a listener when the return function is called', () => {
+    it('should deregister a listener when the return function is called, but only after flush',
+       () => {
+         const engine = new NoopAnimationEngine();
+         const elm = {};
+
+         const fn1 = engine.listen(elm, 'trig1', 'start', capture('trig1-start'));
+         const fn2 = engine.listen(elm, 'trig2', 'done', capture('trig2-done'));
+
+         engine.setProperty(elm, 'trig1', 'value1');
+         engine.setProperty(elm, 'trig2', 'value2');
+         engine.flush();
+         expect(captures).toEqual(['trig1-start', 'trig2-done']);
+
+         captures = [];
+         engine.setProperty(elm, 'trig1', 'value3');
+         engine.setProperty(elm, 'trig2', 'value4');
+
+         fn1();
+         engine.flush();
+         expect(captures).toEqual(['trig1-start', 'trig2-done']);
+
+         captures = [];
+         engine.setProperty(elm, 'trig1', 'value5');
+         engine.setProperty(elm, 'trig2', 'value6');
+
+         fn2();
+         engine.flush();
+         expect(captures).toEqual(['trig2-done']);
+
+         captures = [];
+         engine.setProperty(elm, 'trig1', 'value7');
+         engine.setProperty(elm, 'trig2', 'value8');
+         engine.flush();
+         expect(captures).toEqual([]);
+       });
+
+    it('should fire a removal listener even if the listener is deregistered prior to flush', () => {
       const engine = new NoopAnimationEngine();
       const elm = {};
 
-      const fn1 = engine.listen(elm, 'trig1', 'start', capture('trig1-start'));
-      const fn2 = engine.listen(elm, 'trig2', 'done', capture('trig2-done'));
+      const fn = engine.listen(elm, 'trig', 'start', capture('removal listener'));
+      fn();
 
-      engine.setProperty(elm, 'trig1', 'value1');
-      engine.setProperty(elm, 'trig2', 'value2');
+      engine.onRemove(elm, capture('dom removal'));
       engine.flush();
-      expect(captures).toEqual(['trig1-start', 'trig2-done']);
 
-      captures = [];
-      engine.setProperty(elm, 'trig1', 'value3');
-      engine.setProperty(elm, 'trig2', 'value4');
-
-      fn1();
-      engine.flush();
-      expect(captures).toEqual(['trig2-done']);
-
-      captures = [];
-      engine.setProperty(elm, 'trig1', 'value5');
-      engine.setProperty(elm, 'trig2', 'value6');
-
-      fn2();
-      engine.flush();
-      expect(captures).toEqual([]);
+      expect(captures).toEqual(['dom removal', 'removal listener']);
     });
 
     describe('styling', () => {

modules/@angular/platform-browser/animations/test/noop_browser_animation_module_spec.ts

@@ -63,5 +63,48 @@ export function main() {
         async();
       });
     });
+
+    it('should handle leave animation callbacks even if the element is destroyed in the process',
+       (async) => {
+         @Component({
+           selector: 'my-cmp',
+           template:
+               '<div *ngIf="exp" @myAnimation (@myAnimation.start)="onStart($event)" (@myAnimation.done)="onDone($event)"></div>',
+           animations: [trigger(
+               'myAnimation',
+               [transition(
+                   ':leave', [style({'opacity': '0'}), animate(500, style({'opacity': '1'}))])])],
+         })
+         class Cmp {
+           exp: any;
+           startEvent: any;
+           doneEvent: any;
+           onStart(event: any) { this.startEvent = event; }
+           onDone(event: any) { this.doneEvent = event; }
+         }
+
+         TestBed.configureTestingModule({declarations: [Cmp]});
+         const engine = TestBed.get(ɵAnimationEngine);
+         const fixture = TestBed.createComponent(Cmp);
+         const cmp = fixture.componentInstance;
+
+         cmp.exp = true;
+         fixture.detectChanges();
+         cmp.startEvent = null;
+         cmp.doneEvent = null;
+
+         cmp.exp = false;
+         fixture.detectChanges();
+
+         fixture.whenStable().then(() => {
+           expect(cmp.startEvent.triggerName).toEqual('myAnimation');
+           expect(cmp.startEvent.phaseName).toEqual('start');
+           expect(cmp.startEvent.toState).toEqual('void');
+           expect(cmp.doneEvent.triggerName).toEqual('myAnimation');
+           expect(cmp.doneEvent.phaseName).toEqual('done');
+           expect(cmp.doneEvent.toState).toEqual('void');
+           async();
+         });
+       });
   });
 }