EventBus: Introduces new event bus with emitter backward compatible interface (#27564)

* updated

* Experimenting with event bus with legacy support

* Before switch to emitter

* EventBus & Emitter unification

* Everything using new EventBus

* Making progress

* Fixing merge issues

* Final merge issues

* Updated

* Updates

* Fix

* Updated

* Update

* Update

* Rename methods to publish and subscribe

* Ts fixes

* Updated

* updated

* fixing doc warnigns

* removed unused file

public/app/core/specs/backend_srv.test.ts

@@ -1,10 +1,9 @@
 import 'whatwg-fetch'; // fetch polyfill needed for PhantomJs rendering
 import { Observable, of } from 'rxjs';
 import { delay } from 'rxjs/operators';
-import { AppEvents, DataQueryErrorType } from '@grafana/data';
+import { AppEvents, DataQueryErrorType, EventBusExtended } from '@grafana/data';
 
 import { BackendSrv } from '../services/backend_srv';
-import { Emitter } from '../utils/emitter';
 import { ContextSrv, User } from '../services/context_srv';
 import { describe, expect } from '../../../test/lib/common';
 import { BackendSrvRequest, FetchError } from '@grafana/runtime';
@@ -35,9 +34,11 @@ const getTestContext = (overides?: object) => {
     };
     return of(mockedResponse);
   });
-  const appEventsMock: Emitter = ({
+
+  const appEventsMock: EventBusExtended = ({
     emit: jest.fn(),
-  } as any) as Emitter;
+  } as any) as EventBusExtended;
+
   const user: User = ({
     isSignedIn: props.isSignedIn,
     orgId: props.orgId,

public/app/core/specs/emitter.test.ts

@@ -1,67 +0,0 @@
-import { Emitter } from '../utils/emitter';
-import { eventFactory } from '@grafana/data';
-
-const testEvent = eventFactory('test');
-
-describe('Emitter', () => {
-  describe('given 2 subscribers', () => {
-    it('should notfiy subscribers', () => {
-      const events = new Emitter();
-      let sub1Called = false;
-      let sub2Called = false;
-
-      events.on(testEvent, () => {
-        sub1Called = true;
-      });
-      events.on(testEvent, () => {
-        sub2Called = true;
-      });
-
-      events.emit(testEvent, null);
-
-      expect(sub1Called).toBe(true);
-      expect(sub2Called).toBe(true);
-    });
-
-    it('when subscribing twice', () => {
-      const events = new Emitter();
-      let sub1Called = 0;
-
-      function handler() {
-        sub1Called += 1;
-      }
-
-      events.on(testEvent, handler);
-      events.on(testEvent, handler);
-
-      events.emit(testEvent, null);
-
-      expect(sub1Called).toBe(2);
-    });
-
-    it('should handle errors', () => {
-      const events = new Emitter();
-      let sub1Called = 0;
-      let sub2Called = 0;
-
-      events.on(testEvent, () => {
-        sub1Called++;
-        throw { message: 'hello' };
-      });
-
-      events.on(testEvent, () => {
-        sub2Called++;
-      });
-
-      try {
-        events.emit(testEvent, null);
-      } catch (_) {}
-      try {
-        events.emit(testEvent, null);
-      } catch (_) {}
-
-      expect(sub1Called).toBe(2);
-      expect(sub2Called).toBe(0);
-    });
-  });
-});