fix(timer): setInterval should not auto cancel after callback invoked

Author: JiaLiPassion

lib/common/timers.ts

@@ -39,6 +39,12 @@ export function patchTimer(window: any, setName: string, cancelName: string, nam
       try {
         task.invoke.apply(this, arguments);
       } finally {
+        if (task.data && task.data.isPeriodic) {
+          // issue-934, task will be cancelled
+          // even it is a periodic task such as
+          // setInterval
+          return;
+        }
         if (typeof data.handleId === NUMBER) {
           // in non-nodejs env, we remove timerId
           // from local cache

test/common/setInterval.spec.ts

@@ -60,4 +60,35 @@ describe('setInterval', function() {
     }, null, null, 'unit-test');
   });
 
+  it('should not cancel the task after invoke the setInterval callback', (done) => {
+    const logs: string[] = [];
+    const hasTaskSpy = jasmine.createSpy('hasTask');
+    const zone = Zone.current.fork({
+      name: 'interval',
+      onHasTask:
+          (delegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, hasTask: HasTaskState) => {
+            hasTaskSpy(hasTask);
+            return delegate.hasTask(targetZone, hasTask);
+          }
+    });
+
+    zone.run(() => {
+      const timerId = setInterval(() => {
+        logs.push('interval invoked');
+      }, 100);
+      (global as any)[Zone.__symbol__('setTimeout')](() => {
+        expect(logs.length > 0).toBeTruthy();
+        expect(hasTaskSpy)
+            .toHaveBeenCalledWith(
+                {microTask: false, macroTask: true, eventTask: false, change: 'macroTask'});
+        clearInterval(timerId);
+        expect(hasTaskSpy.calls.allArgs()).toEqual([
+          [{microTask: false, macroTask: true, eventTask: false, change: 'macroTask'}],
+          [{microTask: false, macroTask: false, eventTask: false, change: 'macroTask'}]
+        ]);
+        done();
+      }, 300);
+    });
+  });
+
 });