Support private events in Angular Events Strategy (#338)

Author: ovchinnikov

src/core/events-strategy.ts

@@ -2,7 +2,6 @@ import { EventEmitter, NgZone } from '@angular/core';
 import { DxComponent } from './component';
 
 const dxToNgEventNames = {};
-const nullEmitter = new EventEmitter<any>();
 
 interface EventSubscriber {
     handler: any;
@@ -15,8 +14,7 @@ export class NgEventsStrategy {
     constructor(private ngZone: NgZone, private component: DxComponent) { }
 
     hasEvent(name: string) {
-        let emitter = this.getEmitter(name);
-        return emitter !== nullEmitter && emitter.observers.length;
+        return this.getEmitter(name).observers.length;
     }
 
     fireEvent(name, args) {
@@ -44,7 +42,11 @@ export class NgEventsStrategy {
     dispose() {}
 
     private getEmitter(eventName: string): EventEmitter<any> {
-        return this.component[dxToNgEventNames[eventName]] || nullEmitter;
+        let ngEventName = dxToNgEventNames[eventName];
+        if (!this.component[ngEventName]) {
+            this.component[ngEventName] = new EventEmitter();
+        }
+        return this.component[ngEventName];
     }
 }
 

tests/src/core/component.spec.ts

@@ -331,4 +331,22 @@ describe('DevExtreme Angular 2 widget', () => {
         instance.option('testOption', 'new value');
     }));
 
+    it('should fire unknown subscribed events', async(() => {
+        TestBed.overrideComponent(TestContainerComponent, {
+            set: {
+                template: '<dx-test-widget></dx-test-widget>'
+            }
+        });
+
+        let fixture = TestBed.createComponent(TestContainerComponent);
+        fixture.detectChanges();
+
+        let instance = getWidget(fixture);
+
+        instance.on('unknownEvent', function() {
+            expect(this).toBe(instance);
+        });
+        instance.fireEvent('unknownEvent');
+    }));
+
   });